A sample of radioactive waste has a half-live of 40 years and an activity level of 4 curies. After how many years will the activity level of this sample be 0. 5 curies?

Answers

Answer 1

After 160 years, the activity level of the sample will be 0.5 curies.

What is half-life?

Half life of any radioactive waste is the half decay of that product.

The formula is [tex]\dfrac{\lambda }{\lambda_1} = 2^\dfrac{a}{b}[/tex]

Where, λ is 4 cruies

λ1 is 0.5 cruies

b = 40 years

Putting the values in the equation

[tex]\dfrac{4}{0.5} = 2^\dfrac{a}{40}\\\\\\\dfrac{a}{40} = 4\\ = 160 years[/tex]

Thus, the correct option is 160 years.

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Related Questions

what are the advantages of wind energy/fuel?

have complete details and also add the disadvantages

Answers

Answer:

Advantages of Wind Energy -

Free , clean , unlimited fuel . One of the Cleanest Forms of Energy · Advances in Technology · Doesn't Disrupt Farmland Operations ·5) Reduces Our Dependence of Fossil Fuels

Disadvantages of Wind Energy-

Dangerous to Some Wildlife NoisyExpensive Upfront CostUnreliable/Unpredictable

https://justenergy.com/blog/wind-energy-pros-and-cons/

hope this site might help you with the details


groundwater is an important resource for all life on earth. as you have read, water levels in the ogallala aquifer are decreasing. one proposed
strategy mentioned in the article is to dig deeper wells. do you agree or disagree with this strategy? use evidence and scientific reasoning to
support your position

Answers

Digging of wells being able to increase aquifer is something I agree with.

What is an Aquifer?

This is a water permeable rock layer which is found in the underground layer of the earth.

Wells will ensure water seeps into these layers thereby bringing about an increase in the aquifer.

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Help!! fast pls. what is the second quantum number for one of the electrons in the 4p energy sub level of bromine

Answers

The second quantum number for one of the electrons in the 4p energy sub level of bromine is l = 1 .

What are Quantum Numbers ?

Those set of numbers which describe the energy level and position of an electron are called Quantum Numbers.

There are 4 types of quantum numbers :

Principle Quantum Numbers

Azimuthal Quantum Number  

Magnetic Quantum Number

Spin Quantum number

the bromine atom the one electron in 4p energy sublevel,

 it is in 4rd shell , n= 4 ,

it is in 'p' orbital l = 1

therefore value of m = -1 , 0, 1

[tex]\rm m_s[/tex] = +1/2 or -1/2

The second quantum number for one of the electrons in the 4p energy sub level of bromine is l = 1 .

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CH3NH₂ + H2O → what is this equal

Answers

The balanced equation is CH₃NH₂ + H₂O → CH₃NH + H₃O.

What is a chemical reaction?

A chemical reaction is a reaction involves two or more reactants that reacts to form products.

When methyl amine reacts with water, then methyl amino and hydronium ion are formed.

Thus, the product of the reaction is CH₃NH₂ + H₂O → CH₃NH + H₃O.

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Sulphuric acid (H2SO4) is extremely corrosive to skin. Which branch of chemistry is this?
1) Analytical Chemistry
2) Bio Chemistry
3) Environmental Chemistry
4) Inorganic Chemistry

Answers

It could be bio chemistry since bio chem is the study of mixing chemistry with living organisms. It seems that pouring sulphuric acid on skin is a sign of bio chem

Answer:

B

Explanation:

Bio Chemistry.

Type the correct answer in each box. express your answer to two significant figures. you form water vapor by mixing oxygen and hydrogen at 730°c in a 5.4-liter container. this is the equation for the reaction: o2(g) 2h2(g) → 2h2o(g). the partial pressure of oxygen before the reaction is 122.3 kilopascals, and there is excess hydrogen. how many moles of water are formed? the reaction produces moles of water.

Answers

The number of moles of water vapor formed in the reaction is 0.158 moles

What is the ideal gas equation?

The ideal gas equation shows the relationship between number of moles, temperature, volume and pressure.

Now;

P = 122.3 kilopascals or 1.21 atm

V = 5.4 L

T = 730°c or 1003 K

n = ?

R = 0.082 atmLK-1mol-1

PV = nRT

n = PV/RT

n =  1.21  *  5.4/0.082 * 1003

n = 6.53/82.2

n = 0.079 moles

The equation of the reaction is; O2 (g) + 2H2(g) ---->2H2O(g)

If 1 mole of O2 formed 2 moles of H2O

0.079 moles of O2 yield x moles of H2O

x = 0.079 * 2/1

= 0.158 moles

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When adding sugar to tea, it was observed that the sugar kept dissolving. After a
minute, all of the sugar was completely dissolved, as no extra particles can be
added and be seen floating around. The mixture is then considered to be

Answers

Answer: When adding sugar to tea, it was observed that the sugar kept dissolving. After a minute, all of the sugar was completely dissolved, as no extra particles can be added and be seen floating around.  The mixture is then considered to be

Explanation:

The molecule of  mixture  cannot be seen hence, it will be considered as homogeneous mixture.

What is molecule?

A molecule is just a collection of more than two atoms bound together by chemical bonds; depending on the context, the phrase doesn't have to include ions that meet this requirement.

What is homogeneous mixture?

Solids, liquids, as well as gases, can all be homogeneous mixtures. Through, they have almost the same look and chemical makeup.

When sugar will be dissolved, the sucrose molecules get separated from one another. The materials that make up individual molecules stay together like sucrose molecules sucrose molecules, so the molecule will not break up.

Therefore mixture can be considered as molecule and homogeneous mixture.

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An automobile gasoline tank holds 25.0 gal when full. how many pounds of gasoline will it hold if the gasoline has a density of 0.737 g/ml ?

Answers

The amount (in pounds) the gasoline tank will hold when full is 153.76 lb

What is density?

The density of a substance is simply defined as the mass of the subtance per unit volume of the substance. Mathematically, it can be expressed as

Density = mass / volume

How to convert gallon to milliliters

1 gallon = 3785.412 mL

Therefore,

25 gallon = 25 × 3785.412

25 gallon = 94635.3 mL

How to determine the mass Density = 0.737 g/mLVolume = 94635.3 mLMass =?

Mass = Density × Volume

Mass = 0.737 × 94635.3

Mass = 69746.2161 g

How to convert grams to pounds

453.592 g = 1 lb

Therefore,

69746.2161 g = 69746.2161 / 453.592

69746.2161 g = 153.76 lb

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The rocks that make up the crust are relatively cold and ?

Answers

Answer:

brittle

Explanation:

People in the southern united states imported the plant kudzu from japan to control erosion along highways kudzu now spreads so quickly that it kills many
other plants. how have humans directly impacted the environment in this example?
a introduction of a non-native species
b destruction of habitat
c disruption of a food chain
d. overexploitation

Answers

Humans directly impacted the environment by destroying of the habitat of the other plants. Hence, option B is correct.

What is Kudzu plant?

Kudzu vine is known as a fast-growing plant since the '30s and 40's when the Soil Conservation Service paid about 8$ to every farmer who can plant an acre with this plant.

Kudzu overgrows and crowds out native plant population, for sunlight and nutrients. Therefore, it's considered 'invasive'.

It grows so quickly that it cannot be controlled and disturb other habitats of plants. Hence, option B is correct.

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The substances sodium (Na), oxygen (O2), and sodium oxide (Na2O) participate in this chemical reaction:
4Na + O2 → 2Na2O.
Which statement best describes the reaction?

Answers

The chemical reaction involving sodium and oxygen as given in the reaction: 4Na + O2 → 2Na2O is a synthesis reaction.

What are chemical reactions?

Chemical reactions are changes which occur in the chemical composition of atoms of substances which results in the formation of new substances.

There are different types of chemical reactions such as:

synthesis reactiondisplacement reactiondouble displacement reactions

A synthesis reaction is a reaction in which two or more substances combine to form a new product.

Therefore, the chemical reaction involving sodium and oxygen as given in the reaction: 4Na + O2 → 2Na2O is a synthesis reaction.

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Which electrochemical cell does the illustration depict

Answers

Answer:

This depicts an electrolytic cell.

The half-life of carbon-14 is approximately 5700 years. An archaeologist unearths a piece of wood that is determined to
have 83% of its carbon-14 remaining. Using carbon-12 dating techniques, approximately how old is the ancient piece of
wood that she located?

Answers

The age of the ancient piece of wood that she located given the data is 1482 years

How to determine the number of half-lives

Original amount (N₀) = 100%

Amount remaining (N) = 83%

Number of half-lives (n) =?

2ⁿ = N₀ / N

2ⁿ = 100 / 83

2ⁿ = 1.2

Take the Log of both side

Log 2ⁿ = Log 1.2

nLog 2 = Log 1.2

Divide both side by Log 2

n = Log 1.2 / Log 2

n = 0.26

How to determine the age

Number of half-lives (n) = 0.26

Half-life (t½) = 5700 years

Time (t) =?

t = n × t½

t = 0.26 × 5700

t = 1482 years

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Below is the thermochemical equation for the combustion of octane.

SC8H18(l) + 25O2(g) ⇒ 16CO2 (g) + 18H2O(l), ΔH= -10,941kj


How much heat is released during the combustion of 4 moles of octane (C8H18)

Question 5 options:

-21,882 kJ


-175,056 kJ


-2,735 kJ


-10,941 kJ


Impossible to answer this question with the information provided


-5,470.5 kJ

Answers

5mol produces -10.941KJ

4 mol let produces x KJ

Solve through proportion

5/-10.941=4/x5x=-43.764x=-43.764/5x=8.756 KJ

5moles of octane produces -10941KJ

1mol of octane produces 2188KJ

4mol of octane produces

2188(4)8756KJ

how many moles of pb(NO3)2 are needed to react with 4.8 moles of Al

Answers

If the mole ratio (the number beside each element in the equation on the left side) is 1:1, you’ll need the same amount, so 4.8 moles of Pb(NO3)2!

Activity 1: "PEA-ce of Cake"

OBJECTIVE: Identify the genotypic and phenotypic ratios of offspring in the standard monohybrid cross.

Parent 1: _______________
Garden pea plant with homozygous gene pair for round seed
Garden pea plant with homozygous gene pair for wrinkled seed

Genotype (Parent 1): _______________
RR
rr

Parent 2: _______________
Garden pea plant with homozygous gene pair for round seed
Garden pea plant with heterozygous gene pair for round seed

Genotype (Parent 2): _______________
RR
Rr

Answers

The genotype and phenotype ratio for the first cross will be 100% Rr and 100% round seeded while that of the second cross will be 1RR:1Rr and 50/50 round/wrinkle seeded offspring respectively.

Genotype and phenotype ratio

For the first cross:

                         RR   x   rr

                      Rr   Rr   Rr   Rr

Genotype ratio: 100% Rr

Phenotype ratio - 100% round seeded

For the second cross:

                        RR    x    Rr

                      RR   Rr   RR   Rr

Genotype ratio: 1RR:1Rr

Phenotype ratio = 50% round seeded and 50% wrinkle seeded.

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a student used a vernier magnetic field sensor to measure the strength of the magnetic field generated by a bar magnet. at which position is the
strength of the magnetic field strongest point a or point b?

Answers

The position is the strength of the magnetic field strongest is is the place where the magnetic field leaves, being point A.

What generates a magnetic field?

When an electrically charged particle moves, it creates a magnetic field. According to the laws of electromagnetism, this magnetic field originates from the variation of the electric field strength.

In the region of the poles we see that the lines of magnetic induction are closer to each other, therefore, we consider that close to the poles the magnetic field is more intense.

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An atom has eight protons and nine neutrons. draw the atomic structure of the atom

Answers

draw eight circles and nine more in a big circle = this represents your nucleus
draw eight electrons (since electrons = protons in neutral elements) outside of it (2 in one ring, then 6 in a second ring)

An atom has eight protons and nine neutrons. The atomic structure of the atom is attached below in image.

What is an atomic structure ?

The term "atomic structure" describes the structure of an atom, which has a nucleus that contains both protons and neutrons . The centre of the nucleus is circled by the negatively charged electrons.

The smallest piece of ordinary matter within an element is called an atom. Protons, neutrons, and electrons are the three subatomic particle types that make up an atom.

An isotope's number is equal to the sum of its protons plus neutrons since their masses are almost identical. Oxygen 16 therefore has 8 protons and 8 neutrons, followed by oxygen 17 with 8 protons and 9 neutrons, and oxygen 18 with 8 protons and 10 neutrons.

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Saturn has a diameter of 74,898 miles. What is its diameter in kilometers? (1
mile = 1.6 kilometers)

Answers

Answer:

119836.8 km

Explanation:

  74 898 miles *  1.6 km / mile = 119836.8 km

PLEASE HELP! WILL GIVE BRAINLIEST:


A gas has a volume of 62.65 L at STP. At what temperature (in oC) would the volume of the gas be 78.31 L at a pressure of 612.0 mm Hg?

Please show the work <3

Answers

2.45 °C

From the Ideal gas law (Combined gas law)

PV/T = P'V'/T' .....eq 1

Where:

P - initial pressure

V - initial volume

T - initial temperature

P' - final pressure

V' - final volume

T' - final temperature.

To proceed we have to make T the subject from eq.1

Which is, T = P'V'T/PV.......eq.2

We have been provided with;

Standard temperature and pressure (STP)

P = 760 mm Hg (SP - Standard Pressure)

T = 273.15 K (ST - Standard Temperature)

V = 62.65 L

P' = 612.0 mm Hg

V' = 78.31 L

T' = ? (what we require)

Therefore, we substitute the values into eq.2

T' =

.

T' = 275.60 K

T = (275.60 - 273.15) ......To °C

T = 2.45 °C

>>>>> Answer

Have a nice studies.

If ba+2 will reacts with n-3, the formula of the compound formed is:
a. ban3
b. ba2n3
c. ban
d. ba3n2

Answers

If [tex]Ba^{+2}[/tex] will reacts with [tex]N^{-3}[/tex], the formula of the compound formed is [tex]Ba_3N_2[/tex].

What is an ionic compound?

Ionic compounds are neutral compounds made up of positively charged ions called cations and negatively charged ions called anions.

Barium is a metal element and Nitrogen is a non-metal element, so they form an ionic compound. To make the formula of an ionic compound, first, we need to see the valence of the atoms, that is, how many electrons it can donate or it has to gain to have 8 electrons in the valence layer (octet rule).

Barium is in family 2, so it has two electrons in its valence layer, so it must donate these two electrons; Nitrogen is in family 15, so it has 5 electrons ins its valence layer and must gain 3 electrons.

Writing the ions they must form:

[tex]Ba^{+2}N^{-3}[/tex]

First came the cation (positive charge), then the anion (negative charge), and the charges must change between them, without the signal, and will inform how many atoms are necessary for which element:

[tex]Ba_3N_2[/tex]

Hence, If [tex]Ba^{+2}[/tex] will reacts with [tex]N^{-3}[/tex], the formula of the compound formed is [tex]Ba_3N_2[/tex].

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If you have 100 ml of water mixed with 100 ml of pollutant, the concentration of pollutant is

Answers

The concentration of pollutants is equal to the concentration of water.

What is concentration?

The concentration of a solution is a measure of the amount of solute that has been dissolved in a given amount of solvent or solution.

The concentration of water is 100 ml and the concentration of pollutants is 100 ml .

Hence, If you have 100 ml of water mixed with 100 ml of pollutant, the concentration of pollutant is equal to water.

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How many moles of a gas are contained in 2.085 L at STP?

A. 0.0931 mol
B. 10.8 mol
C. 10.3 mol
D. 1.11 mol

Answers

Answer /-

A.0.0931 mol

from ideal gas equation ,

We have ,

PV = nRT

Where P stands where pressure of gas.
We know that pressure of gas at STP = 1 atm

V stands for volume of gas , given Volume is 2.085 L

R stands for gas constant , R = 0.0821

And T stands for absolute temperature and measured in kelvin,T=273K

Now ,

PV = nRT

n = PV/RT

Refer attachment for working

Based on Figure 2, which statement best describes what happens to the amount of matter in the reaction?

A. There are 54 atoms in the reactants and 54 atoms in the products.

B. There are 15 reactants molecules that become the 15 product atoms.

C. The 15 reactants molecules are destroyed to produce energy in the form of energy

D. The fuel molecule is broken in half and each half makes molecules of water and carbon dioxide as products.​

Answers

Answer:15 +18

Explanation:15 fuel +18 oxygen + 33 cd

A 57.6 g sample of methane (CH4) is found to contain 43.2 g of carbon. What is the
percent composition of Carbon and Hydrogen? How much hydrogen (in grams) would a
37.8 g sample of methane contain?

Answers

Answer:

Explanation:

The atomic mass of carbon is 12.011 g/mol.The atomic mass of hydrogen is 1.00794 g/mol.

This means that the atomic mass of methane is 12.011+4(1.00794)=16.04276 g/mol.

The percent composition by mass of carbon is [tex]\frac{12.011}{16.04276} \times 100=\boxed{74.9\%}[/tex]The percent composition by mass of hydrogen is [tex]\frac{4(1.00794)}{16.04276} \times 100=\boxed{25.1\%}[/tex]

This means that in a 37.8-gram sample of methane, there would be [tex](37.8)\left(\frac{25.1}{100} \right)=\boxed{9.49}[/tex] grams of hydrogen.

Water is made of polar molecules, and oil is made of nonpolar molecules. Based on your observations, which molecules attract each other more strongly, polar molecules or nonpolar molecules? Explain your reasoning.

Answers

Based on observation of polar and non-polar molecules, polar molecules would attract each other more strongly.

What are polar and non-polar molecules?

Polar molecules are those molecules that can ionize or dissociate into their respective positive and negative ions when in an aqueous solution.

Nonpolar molecules, on the other hand, are not ionic i.e. not dissociating into ions when dissolved in water.

Polar molecules like water (H2O) contains an uneven distribution of cations (+) and anions (-), hence, would be more attracted to one another than nonpolar molecules that have an even distribution of ions.

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NEED ASAP PLS WILL AWARD BRAINLIEST
The table compares some characteristics of two atoms.
Charged Particles
Atom Number of Neutrons Mass Number
X 6 12
Y 7 13


Use the table to determine the number of protons for each atom. Then, choose the statement below that is true about the two atoms.
Atom X and Atom Y are in the same row, but not the same family, on the periodic table.
Atoms X and Atom Y are in the same family, but not the same row, in the periodic table.
Atom X is in a column to the right of Atom Y in the periodic table.
Atom X and Atom Y occupy the same position in the periodic table because they are isotopes.

Answers

Answer:

proton number for element X is 6

while proton number for element Y is 7

X and Y are in the same row but not the same family on the periodic table cause element X belongs to group 6 also known as carbon family while Y belongs to group 7 also known as nitrogen family

Select the atoms that belong to the same element.

16 protons 16 neutrons 16 electrons
11 protons 10 neutrons 11 electrons 13 protons 14 neutrons 13 electrons. 14 protons 14 neutrons 14 electrons. 11 protons 12 neutrons 11 electrons

Answers

Explanation:

please structure your question correctly so that we can answer.

Answer:

Cant answer until its wrote correctly

Explanation:

Because its not stated properly

1. Which term identifies a factor that will shift a
chemical equilibrium?
A) atomic radius
B) catalyst
C) decay mode
D) temperature

Answers

Answer:

D) Temperature,

Explanation:

The conductance of the electric current through the electrolytic solution increases with
a)decrease in dilution
b)increase in dilution
c)increase in concentration
d)low degree of ionization

Answers

The conductance of the electric current through the electrolytic solution increases with increase in concentration.

What is an electrolytic solution?

An electrolytic solution is a solution containing dissolved electrolyte.

The ions of the electrolyte dissociate and are able to carry electric current around the electrolytic cell.

The higher the concentration of the electrolyte, the more electric current it can conduct due to greater number of ions present.

Therefore, the conductance of the electric current through the electrolytic solution increases with increase in concentration.

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Other Questions
If you're looking in a book for the chapter called "Eating Healthy: The Latest Information" where would you look? Group of answer choices at the table of contents online in the book's index at the library Grandma baked 969696 cookies and gave them to her grandchildren. One of the grandchildren, Cindy, received ccc fewer cookies than she would have received had all of the cookies been evenly divided among the 888 grandchildren.How many cookies did Cindy receive? 100 points25- For a space both men weresilent, turning over in theirminds the wonderful changesthat this dramaticreconciliation would bringabout. In the cold, gloomyforest. with the wind tearing infitful gusts through the nak3dbranches and whistling roundthe tree-trunks, they lay andwaited for the help that wouldnow bring release and succourto both parties. And eachprayed a private prayer thathis men might be the first toarrive, so that he might be thefirst to show honourableattention to the enemy thathad become a friend. Select the correct texts in the passage.Which two lines best reflect how the setting influences Inges daily life?The wall was just a few feet from the home Inge shared with her parents. Aside from her school and other crumbling buildings in their neighborhood, their world was a few rooms in a dull, gray concrete flat with no yard and no trees. The wall was part of the view from the only windows they had, and Inge was drawn to the sounds she often heard from the other sidelaughter, shouting, music, and the noise of busy traffic.One day, as she explored the wall imagining what the sounds meant, she came upon a hole. Her heart thumped wildly as she leaned toward it. Through the hole, Inge caught a glimpse of a whole new world. It was a world of colorreds, blues, and yellows in the dresses of women strolling down the street, the colors of the shirts and ties the men wore, the colors of the ribbons in the little girls' braids. It was a world of people who did not begin and end each day in shades of gray. It was alive and brimming with activity, with living. Inge leaned, transfixed by the view, for hours until she began to feel the strain in her back and leg muscles. Then, pulling herself away, she headed home, knowing she would return again and again.One fall day in 1990, as Inge headed for her favorite spot in the wall, she noticed that the towers from which the guards viewed her neighborhood were empty. And she noticed something else: she was not alone. Others, mostly young men with a mix of other people, some of whom she recognized were at already at the wall or moving toward it. Identify the balanced chemical equation that represents a single displacement reaction.CF 4 + 2Br 2 CBr 4 + 2F 23H 2SO 4 + 2Al Al 2(SO 4) 3 + 3H 2CF 4 + Br 2 CBr 4 + F 23H 2SO 4 + 2Al Al 2(SO 4) 3 + H 2 A person is accompanied on board a motorboat by a parent or guardian. How old must the person be to operate the boat?. What does it mean to have a negative savings rate?A) Saving for something that is a want instead of a needB) Having a fully funded emergency fundC) Having no savings at allD) Spending more money than you make and acquiring debt 1979 marked the fall of the _____ and the installment of religious leader ayatollah Khomeni.a, king of Iranb, shah of Iran c, Saigond, Vietname, none of the abovehelp Can I Get Some Help With This Please Brainliest Please Nothing dum Using Walter de la Mares poem, Music, as a model, write a three (3) stanza poem where you express what happens to you when music sounds.Remember these important directions:Begin each stanza with When music sounds.Include four (4) lines per stanza.Include imagery that appeals to the sense(s) of the reader throughout the poem.Use punctuation, capitalization, spelling, and grammar appropriately.Start thinking about and add a creative title that fits your poem. (Be aware that your title may change as you continue to write and revise your poem.)When music sounds, gone is the earth I know,And all her lovely things even lovelier grow;Her flowers in vision flame, her forest treesLift burdened branches, stilled with ecstasies.When music sounds, out of the water riseNaiads whose beauty dims my waking eyes,Rapt in strange dreams burns each enchanted face,With solemn echoing stirs their dwelling-place.When music sounds, all that I was I amEre to this haunt of brooding dust I came;And from Time's woods break into distant songThe swift-winged hours, as I hasten along. How many solutions exist for each system of equations?x + 2y = 12x + 3y = 0 There are 5 dessert courses in a restaurant. They will be presented two at a time in an order. How many different arrangements are there? 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Match each online banking security practice with the PCI security requirement that mandates it.vulnerability management programcredit card data protectionstrong access controlssecure networkencrypting transfer of card datainstalling a firewallinstalling antivirus softwareassigning unique IDs and user names Imperial rivalries and military buildups in 20th-century Europe created a situation in which: A. disagreements among European states could easily erupt into armed conflicts. B. small countries tried to become part of large empires for their own protection. C. republican governments in Europe were overthrown by military dictators.D. European countries were unwilling to form military alliances with their neighbors. Describe one specific way that the two disasters detailed above contributed to the decline of the Roman empire Find the HCF of ax3y and bx4y3 What were some ways political machines hurt cities?A. People without ability or experience became officials.B. Immigrants received help and could stay in America.C. Corrupt leaders were kept out of power.D. People worked to stop government corruption