Can someone help me I dont know what to do

Answer:

I did the work and uploaded the answers i hope it helped!!

[tex]\large\displaystyle\text{$\begin{gathered}\sf 1) \ \left\{\begin{matrix} 5x-3y-z=1&\\ x+4y-6z=-1& \\ 2x+3y+4z=9& \end{matrix}\right. \end{gathered}$}[/tex]

The coefficient matrix associated with the system is constructed and the columns and rows are reduced.

                [tex]\left ( \begin{array}{ccc|c} 5 & -3 &-1 &1\\ 1 & 4 & -6 &-1\\ 2 & 3 & 4 & 9 \end{array} \right ) \begin{array}{c} \xrightarrow[\textup{F}_3- 2\textup{F}_2]{\textup{F}_1 - 5\textup{F}_2} \end{array} \left ( \begin{array}{ccc|c} 0 & -23& 29 &6\\ 1 & 4& -6 &-1\\ 0 & -5 &16 & 11 \end{array} \right )\\ \ \\ \ \\ \begin{array}{c} \xrightarrow[]{23\textup{F}_3 - 5\textup{F}_1} \end{array} \left ( \begin{array}{ccc|c} 0 & -23& 29 &6\\ 1 & 4& -6 &-1\\ 0 & 0 & 223 & 223 \end{array} \right )[/tex]

So, z=1. Translating the last matrix to the associated system of equations, we have that x=1, y=1, since:

                                       [tex]\large\displaystyle\text{$\begin{gathered}\sf \begin{align*} y&=\dfrac{6-29}{-23}=\dfrac{-23}{-23}=1\\ x = -1+6-4=1 \end{gathered}$}[/tex]

[tex]\large\displaystyle\text{$\begin{gathered}\sf \bf{2) \ \left\{\begin{matrix} x+y=7& \\ x\times y=12& \end{matrix}\right. } \end{gathered}$}[/tex]

Clear an unknown in the first equation and substitute the resulting expression in the second. Next, the quadratic equation is solved.

             [tex]\large\displaystyle\text{$\begin{gathered}\sf \bf{ y=7-x \quad \Longrightarrow \quad 12=x(7-x)=7x-x^2 } \end{gathered}$}[/tex]

                    [tex]\large\displaystyle\text{$\begin{gathered}\sf \bf{ 0=x^2-7x+12=(x-4)(x-3); } \end{gathered}$}[/tex]

                [tex]\large\displaystyle\text{$\begin{gathered}\sf \bf{ x_1=4\qquad x_2=3 \Longrightarrow y_1=3 \qquad y_2=4 } \end{gathered}$}[/tex]

[tex]\large\displaystyle\text{$\begin{gathered}\sf \boldsymbol{3) \ \left\{\begin{matrix} x^2+y^2=169& \\ x+y=17& \end{matrix}\right. } \end{gathered}$}[/tex]

Clear an unknown in the first equation and substitute the resulting expression in the second. Next, the quadratic equation is solved.

[tex]\large\displaystyle\text{$\begin{gathered}\sf \boldsymbol{ y=17-x \quad \Longrightarrow \quad 169=x^2 +(17-x)^2=x^2+x^2 -34x+289 } \end{gathered}$}[/tex]

[tex]\large\displaystyle\text{$\begin{gathered}\sf \boldsymbol{ 0=2x^2-34x+120=2(x^2-17+60)=2(x-12)(x-5); } \end{gathered}$}[/tex]

               [tex]\large\displaystyle\text{$\begin{gathered}\sf \boldsymbol{ x_1=4\qquad x_2=3 \Longrightarrow y_1=3 \qquad y_2=4 } \end{gathered}$}[/tex]

[tex]\large\displaystyle\text{$\begin{gathered}\sf \pmb{4 \ \left\{\begin{matrix} y^2-2y+1=x & \\ \sqrt{x}+y=5 & \end{matrix}\right. } \end{gathered}$}[/tex]

Substitute the expression that represents x into the second equation. Then both sides of the equation are squared and solved.

   [tex]\large\displaystyle\text{$\begin{gathered}\sf \pmb{ \sqrt{y^2-2y+1}+y=5\quad \Longrightarrow\quad \left ( \sqrt{y^2-2y+1} \right )^2=(5-y)^2 } \end{gathered}$}[/tex]

                  [tex]\large\displaystyle\text{$\begin{gathered}\sf \pmb{ y^2-2y+1=y^2-10y+25\quad \Longrightarrow\quad 8y=24; } \end{gathered}$}[/tex]

                                     [tex]\large\displaystyle\text{$\begin{gathered}\sf \pmb{ y=6 \qquad x=4 } \end{gathered}$}[/tex]

Answer:

2

Step-by-step explanation:

-3 (4 - 7) + (2 x 5 - 17)

 -3 (4 - 7) + (10 - 17)

 -3 x (-3) + (-7)

   9 + (-7)

 9 - 7

   =2

Answer:

∠ABC = 55°

Step-by-step explanation:

Alternate Interior Angles Theorem

If a line (AC) intersects a set of parallel lines (m and n) in the same plane at two distinct points, the alternate interior angles that are formed are congruent.

⇒  ∠BAC = ∠DCA

⇒  ∠BAC = 50°

The interior angles of a triangle sum to 180°

⇒ ∠BCA + ∠BAC+ ∠ABC = 180

⇒ 75 + 50 + ∠ABC = 180

⇒ ∠ABC = 180 - 75 - 50

⇒ ∠ABC = 55°

Answer:

B: 12.5%

Step-by-step explanation:

You take the 20.000- 8.500 the number decreased with= 11.5.

You then round of your answer to the nearest 10th, the number 11,5 will change to 12,50.

Answer:

x = 30

Step-by-step explanation:

The sum of the angles of a triangle add to 180

x+2x+3x = 180

Combine like terms

6x= 180

Divide each side by 6

6x/6 = 180/6

x = 30

The probability of winning the game on your next turn is; 14%

The sample size of the two number cubes, when rolled is:

n = 36

The number of outcomes that give a sum of 2 or 5 is 5,

And the outcomes are (1, 1) (2, 3) (3, 2) (1, 4) (4, 1)

The probability is the quotient of the number of outcomes of the sum of 2 or 5 and the total outcomes.

Thus,

Probability = 5/36 * 100% = 13.89% ≈ 14%

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Multiply the moduli and add the arguments:

√2/6 cis(3π/5) × √6/4 cis(2π/3)

= (√2/6 × √6/4) cis(3π/5 + 2π/3)

= √3/12 cis(19π/15) … [A]

Answer: 9 cups

Step-by-step explanation: 8 multiply it by 9 .

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[tex]\diamond\large\textsf{\textbf{\underline{Given question:-}}}[/tex]

                Solve the following equation for b.

13b=6b+14

[tex]\diamond\large\blue\textsf{\textbf{\underline{\underline{Answer and how to solve:-}}}}[/tex]

❖ First of all, we need to make sure that all the variables are on one side (the left-hand side, LHS) and numbers are on the right-hand side, RHS.

Here we have variables on the right-hand side, so we can move that term to the left-hand side, making sure to use the opposite operation:-

13b=6b+14              Subtract 6b on both sides, which results in:-

7b=14                      Divide by 7 on both sides, which results in:-

b=2                         We've found the value of b. Now, we need to check our solution by replacing b with the value of b, 2, and seeing whether or not we end up with a true statement:-

13(2)=6(2)+14                 Multiply.

26=12+14                       Now add.

26=26                          Since the left-hand side does equal the right-hand side, we conclude that our solution, b=2, is correct.

           - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Answer:

2 15/28

Step-by-step explanation:

First we will convert both mixed fractions into improper fractions.

5 1/4 becomes 21/4

2 5/7 becomes 19/7

21/4 - 19/7 does not work, so we must make the denominator the same

147/28 - 76/28 = 71/28

Now we convert back to a mixed number:

2 15/28

Answer: [tex]-11\frac{15}{28}[/tex]

Step-by-step explanation:

Convert to Improper fractions

[tex]5\frac{1}{4} = \frac{21}{4} \\2\frac{5}{7} = \frac{19}{7} \\[/tex]

Find a lowest common multiple

lcm(4,7) = 28 (7 * 4)

since they are just multiplying each other, we can cross multiply

[tex]\frac{(21*7) - (19*4)}{4*7} = \frac{147-76}{28} \\= \frac{71}{28} \\=2\frac{15}{28}[/tex]

Answer:

9/1000

Step-by-step explanation:

When writing decimals into fractions, you first take the last digit, (in this case 9), and place it as your numerator, then count how many decimal places there are after 0. <---- in our case we have 3 decimal places which means our denominator has 3 zeros. Hence it is 1000.

Answer:

y = 10

Step-by-step explanation:

if the figure is to be a parallelogram, then

∠ ACB and ∠ DAC are alternate angles and are congruent , that is

5y - 13 = 7 + 3y ( subtract 3y from both sides )

2y - 13 = 7 ( add 13 to both sides )

2y = 20 ( divide both sides by 2 )

y = 10

Answer:

The number is 740

Step-by-step explanation:

Hello!

Let the number that we want to solve for be x.

100% of x is x, but a decrease of 5% if 95% of x.

The number is 740.

The solution is correct.

Answer:

x = 4

Step-by-step explanation:

x(x + 8) = 48

x² + 8x = 48

x² + 8x - 48 = 0

times into -48

add into 8

(x - 4)(x + 12) = 0

x - 4 = 0

x = 4

or

x + 12 = 0

x = -12

A length cannot be a negative number therefore x = 4

Answer: Total cost/month = 7 + 3x

Step-by-step explanation:

This is only the total cost per month that is why it is only 7 and 3x since the number of downloaded games is not given.

I'm not sure about my answer but I hope that it helps.

£3.50 for each burger

3.50×4= 14 left over is 6 from the 20 pound note

Answer:

From the diagram you can see that we have constructed a right triangle, with height A and base 15.Length of shadow = 15 feet.Height of flagpole = A.We know the angle of elevation is 40∘. Using this angle and the tangent ratio, we can find A.tan(40∘)=oppositeadjacent=A15∴tan(40∘)=A15Rearranging:A=15tan(40∘)By calculator:A=12.59 feet.  ( 2 d.p.)

Answer:

[tex]\huge\boxed{\sf x(x + 4)}[/tex]

Step-by-step explanation:

Given expression:

x² + 4x

Take x common

x(x + 4)

[tex]\rule[225]{225}{2}[/tex]

Answer:

it's difficult , sorry

Step-by-step explanation:

ask easily one

Answer:

Step-by-step explanation:

800 J/kgC

What is the specific heat of a material that gains 600 joules of energy when a 0.25 kg object increases in temperature by 3C?

it is 800 J/kgC

Answer:

J(-9,-5)

K(-9,3)

L(0,-2)

M(0,-5)

HOPE IT HELP (≧▽≦)(≧▽≦)(≧▽≦)

Answer:

Step-by-step explanation:

the answer is wrong its  34.3

Step-by-step explanation:

reduce -28<4w-8

-7<w-2

add +2

-7+2<w-2+2

-5<w

w>-5

Answer:

See below ~

Step-by-step explanation:

Solving the inequality :

Evaluating the given numbers :

-5

5

-9

-1

Answer:

9.42

Step-by-step explanation:

Since the angle shown is 90 degrees we can deduce that the rest of the arc is 270 degrees therefore we can make the fraction:

270/360; 360 being the total angle measurement of a circle

270/360 simplifies to 3/4

The fraction represents how much of the circle that arc covers

Now we have to find the circumference which would be

2(3.14)r

r = 2 therefore: 2(3.14)2 = 12.56

Now that we have the circumference of the WHOLE circle we multiply it by 3/4 to find out the arc length

Which gives us  9.42

opposite sides and diagonals of a parallelogram are equal

+ diagonals of a parallelogram meet eachother in the middle so:

10x+14=x+77

10x-x=77-14

9x=63

x=63÷9

x= 7

y+8=4y-19

y-4y=-19-8

-3y=-27

y=-27÷-3

y=9

2z+3=37

2z=37-3

2z=34

z=34÷2

z=17

To find the degrees of freedom in the given question, we have to take into consideration of the confidence interval as well as degrees of freedom. The critical t-value in this data set is 2.086

This is the range of values that we observe in our sample and for which we expect to find the value that accurately reflects the population.

We can also say that it is a range of values so defined that there is a specified probability that the value of a parameter lies within it.

Data;

At a 95% confidence level, the t is

α   =  1  -   0.95

The critical t-value in this data set is 2.086

Learn more on t-value here;

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