\sqrt{53+20\sqrt{7}} can be written in the form a+b\sqrt{c}, where a, b, and c are integers and c has no factors which is a perfect square of any positive integer other than 1. Find a+b+c.

Answers

Answer 1
Answer:  14

=====================================================

Explanation:

Since the range of [tex]y = \sqrt{x}[/tex] is [tex]y \ge 0[/tex], this means that [tex]\sqrt{53+20\sqrt{7}}[/tex] cannot be negative.

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

Let's set the given nested radical expression equal to the form a+b*sqrt(c), and then square both sides to see what happens

[tex]\sqrt{53+20\sqrt{7}} = a+b\sqrt{c}\\\\\left(\sqrt{53+20\sqrt{7}}\right)^2 = \left(a+b\sqrt{c}\right)^2\\\\53+20\sqrt{7} = a^2+2ab\sqrt{c}+b^2c\\\\53+20\sqrt{7} = (a^2+b^2c)+2ab\sqrt{c}\\\\[/tex]

Equating the corresponding parts shows that

[tex]53=a^2+b^2c \text{ and } 20\sqrt{7} = 2ab\sqrt{c}\\\\[/tex]

Therefore c = 7 must be the case to allow the radicands to match up.

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

Since c = 7, we can update the first equation like so

[tex]53=a^2+b^2c\\\\53=a^2+b^2*7\\\\53=a^2+7b^2\\\\[/tex]

We'll come back to this later.

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

Focus on [tex]20 = 2ab\sqrt{7}[/tex]

Note how 20 and 2ab are coefficients outside the root. So 20 = 2ab leads to ab = 10.

Here are all the ways to multiply to 10 where a,b are integers

1*10 = 10-1*(-10) = 102*5 = 10-2*(-5) = 10

So we could have these possibilities.

a = 1, b = 10a = 10, b = 1a = -10, b = -1a = -1, b = -10a = 2, b = 5a = 5, b = 2a = -5, b = -2a = -2, b = -5

If you try all of those a,b combinations with [tex]53 = a^2 + 7b^2[/tex], then you should find that a = 5 and b = 2 works. I'm skipping a bunch of steps here. All you basically do is plug and chug.

Due to symmetry, we could have a = -5 and b = -2 as another solution to [tex]53 = a^2 + 7b^2[/tex]. However, if a < 0 and b < 0, then [tex]a+b\sqrt{c}[/tex] would be negative which contradicts the fact that [tex]\sqrt{53+20\sqrt{7}}[/tex] is positive. So we'll ignore any case where a,b are negative.

Therefore, the only combination that works is a = 5 and b = 2

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

Overall, we found that

a = 5b = 2c = 7

And therefore,

[tex]\sqrt{53+20\sqrt{7}} = a+b\sqrt{c}\\\\\sqrt{53+20\sqrt{7}} = 5+2\sqrt{7}\\\\[/tex]

You can confirm this with your calculator by taking advantage of the idea "If x = y, then x-y = 0". In other words, if you subtract the left and right sides, you should get 0 as a result (the order of subtraction doesn't matter in this case). Don't forget to use parenthesis correctly, or you may not get 0. It might help to think of it as the form (x) - (y) = 0.

After we confirmed we have the correct a,b,c values, we simply add them up to get a+b+c = 5+2+7 = 14.


Related Questions

3x - 7x + 2 < 10 - 12

14w - 8w - 5.4 ≥ 7.3- 10

PLS HELP ASAP

Answers

Answer:

first one is x>1

second one is w≥0.45

Step-by-step explanation:

1. −4x+2<10−12

−4x<−2−2

−4x<−4

2. 6w−5.4≥7.3−10

6w≥2.7

Answer:

x>1

w>=0.45

Step-by-step explanation:

I'm assuming you want to simplify the equations.

HELP ME ASAPPPP, i'LL GIVE YOU BRAINLIST!!! NO NONSENSE ANSWERS PLS!
1 SLIDE OPTIONS.
$515
$575
$600
$650
SLIDE 3 OPTIONS
5 percent
15 percent
25 percent
30 percent
SLIDE4 OPTIONS
$87.55
$123.50
$149.22
$218.50

Answers

                          ∧

Answer:

1, 3, and 4

Step-by-step explanation:

Make him Brainliest he was first.

                   

-7z - 59 = -10 what does z =?

Answers

Answer:

-7

Step-by-step explanation:

Answer:

z = - 7

Step-by-step explanation:

-7z = 49 (you add up -59 and -10, 2 - signs = +)

-z = 7 (you do 49 divided by 7)

z = - 7

I think this is right

PLEASE HELP AS SOON AS POSSIBLE :)
At Sally's Diner, combo meals come with either chips or fries. Of the 115 customers on Friday, 80% ordered combo meals. Of these 3/4 had fries. How many customers on Friday had fries with their meals?

A. 69
B. 72
C. 86
D. 92

Answers

Answer:

A: 69

Step-by-step explanation:

80% of 115 customers had combos. To find out the amount that had combos, we multiply the amount of customers by percentage. 115 * 80% (0.8) is 92. 92 customers had combo meals. 3/4 of them had fries with it, and 3/4 is 75% in percent form. We multiply 92 by 75% to get the amount that had fries. 92 * 75% (0.75) is 69. There. Sally's Diner had 69 of Friday's customers order fries with their combo meals.

115 x .80% = 92

92 x .75% = 69

Answer : A. 69

Need help with this. Please don't answer if you're not sure thanks!

Answers

1/9



Explanation:

9(3)^-4

Answer:

C: 1/9

Step-by-step explanation:

You have $3.25 to buy bananas. Each bananas costs $0.35. How many bananas will you buy? Will you use all your money? If not, how much will you have left over?

Answers

Answer:

If had left over I would leave $1.85

Step-by-step explanation:

Select the graph that represents the given set. (Click on the graph until the correct one is showing.) E = {(6, 2), (7, 3), (6, -1), (5, 4)}

Answers

Step-by-step explanation:

the answer is second picture because according to the coordinate which is the first number in the bracket is refer to x axis while the number that after comma is for y axis; (x,y)

Answer:

I didn't know how to put it on here so I provided a screenshot of the correct answer

Step-by-step explanation:

Dean loves rocks! He has 666 pieces of granite, 333 pieces of marble, 141414 pieces of sandstone, and 111 pieces of slate.

What is the ratio of pieces of sandstone to pieces of marble in Dean's collection?

Answers

Answer:

The ratio of sanstone to marble is... 141414 : 333

All you have to do is look at how much sandstone Dean has and how much marble he has, then put the amount of sandstone infront of the amount of marble because in the question it says what is the ratio of sandstone to marble and you see that sandstone is first.

Hope this helps! :)

Stay safe

Wendy did a survey of four bird parks and wrote the following observations:

Bird Park Survey
Park Number of Blue Birds Total Number of Birds
A 23 96
B 41 72
C 40 78
D 24 62
Based on the survey, which park had the greatest percentage of blue birds? (1 point)

Group of answer choices

Park A

Park B

Park C

Park D

Answers

B hope u get it right
i think it’s B , ( park B )

14, 20, 26, 32,... find the 78th term for the arithmetic sequence

Answers

Keep adding 6 and you will find the 78th term!
It’s a pattern you would you the recursive equation, 6Xn1 + 8 if you plugged it in it would be, 6(78) = 468 + 8 the answer would be 476

A laptop has a listed price of $899.95 before tax. If the sales tax rate is 6.5%, find the total cost of the laptop with sales tax included.
Round your answer to the nearest cent, as necessary.

Answers

Answer:

the total cost of the laptop with tax is 958.45

Step-by-step explanation:

The point (1, –5) is reflected across the y-axis. A coordinate plane. What are its new coordinates?
(–1, 5)
(1, –5)
(–1, –5)
(1, 5)

Answers

Answer:  Choice C.   (-1, -5)

Explanation:

The reflection rule we use is

[tex](x,y) \to (-x, y)[/tex]

when we want to reflect over the y axis. The x coordinate flips from positive to negative, or vice versa, while the y coordinate stays the same.

Therefore, [tex](1, -5) \to (-1, -5)[/tex]

the answer is c ...........

The sales tax for an item was $8.80 and it cost $440 before tax.
Find the sales tax rate. Write your answer as a percentage.

Answers

Answer:

Step-by-step explanation:

In non-mathematical form, the question is asking $8.80 is what percent of $440. N will equal the percent. So, you would set up the equation like this: 20 = N · 440

You need to solve the equation.

20/440 = N · 440/440

0.045 repeating = N

Rounded, the sales tax rate would be 4.5%

( -20 , 14 ) and ( 30, 18)
Slope, Explanation needed please HELPPPPPP

Answers

Answer: 2/25

Step-by-step explanation:

The formula to find the slope is (y2-y1)/(x2-x1)

If you plug in the numbers, you get (18-14)/(30-(-20))

Solve the expression and you get 4/50 = 2/25

So your answer is 2/25

Answer:

the slope is 2/25.  use the formula m= y2-y1/x2-x1 and plug in the points

what is the equation of the best fit for this data

Answers

Answer:

i-i think it either A) or C)

Step-by-step explanation:

please help giving brain liest :DDDDDDDDDDDDDDDD

Answers

Answer:

uhh ik ur gonna hate bc of my answer

Step-by-step explanation:

What is the total surface area of this rectangular pyramid?
A rectangular pyramid. The rectangular base has a length of 12 feet and width of 6 feet. 2 triangular sides have a base of 12 feet and height of 8 feet. 2 triangular sides have a base of 6 feet and height of 9.5 feet.
_____________ square feet
HELP PLS!!!

Answers

Answer:

225 square feet

Step-by-step explanation:

the base of the pyramid would be 76 ft², since 12*6=72. Then you get the surface area of the sides. 2 of the sides would be 48 ft², since (12*8)/2=48. The other 2 sides would be 28.5 ft², since (6*9.5)/2-28.5. Then you just add the surface areas of all the sides; 76+48+48+28.5+28.5 to get 225.

Hope this helps! :)

Answer:

(C) 225

Step-by-step explanation:

I took test on edge 2021 got 100%

Shilo is trying to compute the value of 27 + 55 + 13. She adds 27 + 13 to get 40 and then adds on 55. Which of the following properties is Shilo using?
1.) commutative
2.) distributive
3.) identity
4.) associative

Answers

she use commutative property of addition

Answer:

commutative property of addition is your answer

The commutative property of addition states that no matter which terms you add first, the result would be the same

(A) commutative is your answer

Harrison has 70 CDs in his music collection. If 10% of the CDs are country music and 60% are pop music, how many CDs are other types of music?

Answers

Answer:

21

Step-by-step explanation:

The number of CDs of another type of music will be 21.

What is an expression?

Expression in maths is defined as the collection of numbers variables and functions by using signs like addition, subtraction, multiplication, and division.

Numbers (constants), variables, operations, functions, brackets, punctuation, and grouping can all be represented by mathematical symbols, which can also be used to indicate the logical syntax's order of operations and other features.

Given that Harrison has 70 CDs in his music collection. If 10% of the CDs are country music and 60% are pop music.

The percentage of the other CDs will be:-

P = 100 - 60 - 10

P = 30%

The number of the other CDs will be:-

Number = 70 x 30%

Number = 70 x ( 30 / 100 )

Number = 21

To know more about an expression follow

https://brainly.com/question/13882635

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Kyle has three pieces of rope. The lengths of the ropes are 241.6 centimeters, 241.38 centimeters, and 264.7 centimeters.

What is the difference in length between the longest and shortest pieces of rope?

Answers

Answer:

23.32 cm

Step-by-step explanation:

longest - 264.70 cm

smallest -241.38 cm

so 264.70 cm -241.38 cm =23.32 cm

Answer: 23.32 cm (Don't forget your label)

Step-by-step explanation: 264.7 - 241.38 = 23.32 cm

Almonds are a member of the peach family

Answers

faxxxxxxxxxxxxxxxxxxxx

ok ok ok now whats -4 = -20

Answers

Answer:

This is wrong But if you ask me what is -4= -2² and -20= -2×10¹

Answer:

ok ido not know

Step-by-step explanation:

You place a billiard cue against a billiard table. The foot of the billiard cue is 15 cm away from a table and the top of the billiard cue touches the table at a point 60 cm off the ground. what is the slope of the billiard cue?

Answers

Answer:

It would be 4

Step-by-step explanation:

When dealing with slope its always going to be rise over run, so 60/15 is 4

Hope this helps :)

You place a billiard cue against a billiard table. The foot of the billiard cue is 15 cm away from a table and the top of the billiard cue touches the table at a point 60 cm off the ground. what is the slope of the billiard cue?poroso opoo

Alejandro has gone to school StartFraction 5 Over 7 EndFraction of the last 35 days. Which expression can be used to determine the number of days Alejandro has gone to school?35 divided by 7 = StartFraction 5 Over 7 EndFraction
35 times StartFraction 5 Over 7 EndFraction
StartFraction 5 Over 7 EndFraction divided by 35
StartFraction 7 Over 5 EndFraction divided by 35

Answers

Answer:

35 times 5/7

Step-by-step explanation:

5/7 is a decimal and when multiplied by 35 it turns into 25 days. 25/35 is 5/7 so the answer makes sense

Answer:

25 Days

Step-by-step explanation:

Do 5/7 * 5/5 and then you get 25/35 which the numerator is how many days he went out of those 35 days

Please answer the question in the picture that I have provided

Answers

Answer:

i think it b im not to sure

Step-by-step explanation:

Answer:

sqrt 25 is a rational number

Step-by-step explanation:

6x-2y=-2

7x-7y=14


I’ve been using the elimination method but I keep getting the wrong answer. The answer I’m getting is (-3/2,-7/2). I’m just trying to not get fractions as an answer. Thanks for helping out if you can! (I still need to use elimination method without getting a fraction in the ordered pair)

Answers

Answer:

7x-7y=14

x=3 and y= 1

i think :)

Step-by-step explanation:

you’re not wrong! i did the work and got the same thing as you.

Solve the equation.

h + | -8| = 15

Answers

Answer:

if you're trying to say h+ -8 = 15 then h would be 23

these || would mean the -8 is just 8 so it would be 15-8 which is 7

Need help with this math problem

Answers

Answer:

y= -2x plus 16

Step-by-step explanation:

Answer:

y= 2x + 16

Step-by-step explanation:

mark me as brainliest

Bob is packing a suitcase to take on an airplane. A suitcase and its contents can weigh at most 50 pounds before the airlines charge extra fees. Bob's suitcase weighs 10 pounds when it is empty, so he can put 40 pounds of clothes in the suitcase. Bob's shirts weigh 0.5 pounds each and his pants weigh 2 pounds each.

(1)Write an equation that would model how many pounds of clothing Bob can pack.


(2)Rewrite the equation to model the number of pants Bob can pack in terms of the number of shirts.

Answers

Answer:

1. 10x + 40 = 50

2. 10x + 2 + 0.5 = 40

Step-by-step explanation:

1. If bob's suitcase is 10lb. by itself then that is 10.

His limit of content and suitcase is 50lb.

His shirts weigh 0.5lb each.

His pants weigh 2lb each.

10x + 40 = 50

2. 10x + 2 + 0.5 = 40

The Kirkland family is buying a new living room set that costs $1,495.

They are going to put a down payment of $400 and then put the rest on

their credit card that has an annual interest rate of 28%. If they pay off

the furniture in 1 year, how much interest would they pay?

Answers

Answer:   173.04 dollars

======================================================

Explanation:

The down payment is $400, so that means they must pay back 1495-400 = 1095 dollars. Let L = 1095 be the amount loaned

The annual interest rate is 28% which means r = 0.28; the monthly interest rate is i = r/12 = 0.28/12 = 0.02333 approximately

There are 12 months in a year, so n = 12 is the number of payment periods

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

In summary so far, we have

L = 1095i = 0.02333 (which is approximate)n = 12

Those values will be plugged into the monthly payment formula below

M = L*( i*(1+i)^n )/( (1+i)^n - 1 )

M = 1095*( 0.02333*(1+0.02333)^12 )/( (1+0.02333)^12 - 1 )

M = 105.671914631108

M = 105.67

The monthly payment is $105.67

If they have a monthly payment of $105.67, and they pay that for 12 months, then 12*105.67 = 1,268.04 dollars is the amount of money they pay back to the credit card company.

The total amount of interest would be 1,268.04 - 1,095 = 173.04 dollars

Side note: the formula is a complicated ugly mess, so it's understandable to use calculators that already have the formula built in. Many websites offer free calculators that do this.

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