Answer: Choice B

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Explanation:
The two rules we use are


When applying the first rule to the expression your teacher gave you, we can say that:

Then applying the second rule lets us say

Therefore,

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In short, we just multiplied each exponent inside by the outer exponent 1/2.
So that explains why the exponents go from {1/4,16} to {1/8,8} for x and y in that exact order.
Let's see.
4x/5 + 4/3 = 2x
First we have to make each denominator the same, so I'll multiply 4x/5 by 3/3, 4/3 by 5/5, and 2x by 15/15
Now we have 12x/15 + 20/15 = 30x/15
With everything in the same denominator we can solve the new equation of
12x + 20 = 30x
20 = 18x
10 = 9x
X= 10/9
(8c)^2+7c
(8c)^2=64c^2
so that..
64c^2+7c
factor out c
c(64c+7)