Answer:
i.e answer A.
Step-by-step explanation:
This question involves knowing the following power/exponent rule:
![\sqrt[n]{x^m} = x^\frac{m}{n} \\\\so \sqrt[7]{x^2} = x^\frac{2}{7} \\\\and \\\\ \sqrt[5]{y^3} = y^\frac{3}{5} \\](https://tex.z-dn.net/?f=%5Csqrt%5Bn%5D%7Bx%5Em%7D%20%3D%20x%5E%5Cfrac%7Bm%7D%7Bn%7D%20%5C%5C%5C%5Cso%20%5Csqrt%5B7%5D%7Bx%5E2%7D%20%3D%20x%5E%5Cfrac%7B2%7D%7B7%7D%20%5C%5C%5C%5Cand%20%20%5C%5C%5C%5C%20%5Csqrt%5B5%5D%7By%5E3%7D%20%3D%20y%5E%5Cfrac%7B3%7D%7B5%7D%20%5C%5C)
Next, when a power is on the bottom of a fraction, if we want to move it to the top, this makes the power become negative.
so the y-term, when moved to the top of the fraction, becomes:

So the answer is: 
4*-5 is -20 is does not equal -25 so it’s false
Questions:
A clothing manufacturer uses the model a = √(f + 4) - √(36 - f) to estimate the amount of fabric to order from a mill. In the formula, a is the number of apparel items (in hundreds) and f is the number of units of fabric needed. If 400 apparel items will be manufactured , how many units of fabric should be ordered?
Answer:
32 units of fabrics
Step-by-step explanation:
Given

Required
Find f when a = 4
Substitute 4 for a

Rewrite as:

Square both sides



Collect Like Terms


Divide through by 2

Square both sides




Collect like terms


Factorize

or 
f can not be 0 because some units must be ordered.
So, f = 32