Answer: Choice B) 
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Work Shown:

This shows why choice B is the answer.
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Explanation:
- In the second step, I multiplied top and bottom by

- This is so we can apply the difference of squares rule in step 3. The difference of squares rule is (x-y)(x+y) = x^2-y^2.
- In step 4, the square roots cancel out with the squaring operation. The two operations are inverses of one another, which is why they cancel.
So in general, if the denominator is
and you want to rationalize the denominator, then you should multiply top and bottom by
. The same applies in reverse as well.
This leads to the denominator becoming 
Keep in mind that
and 
. The student's conclusion is incorrect because the solution to the system of equations 4x + 2y = 32 and 5x + 2y = 36 is (4, 8).
B is right option
4x + 2y = 32
5x + 2y = 36 subtracting
-x=-4
x=4
4(4)+2y=32
16+2y=32
2y=16
y=8
hope this helps
Answer:
160 books
Step-by-step explanation:
To find the total amount of something, when given the percent and how much value the percent is, use this

This way we get:

Hope this answer helped! :)
Answer:
C 210
Step-by-step explanation:
To solve this, First we must take 42/3, Since it equals 14, we take 15x14 and find 210
(edit: to solve for Kim's missing values, you do the same with 2 and 32)
Firstly, you want to multiply (f^4)^2. 
Next, multiply everything on the numerator. 
Next, divide. 
Now remember that f^-2 = (1/f^2), so just convert the negative powered exponent to that, and your answer will be 