The answer is C. 81.49 !!
Answer:X=13/145
Step-by-step explanation:

To get the 0.12 to repeat, the trick is to subtract 1 from the denominator

Then reduce the fraction.

now add the 3 to get
Multiply then simplify, that's doing the same work twice...anyway
x^3+x^2y+xy^2-x^2y-xy^2-y^3
x^3-y^3 which if factored is:
(x-y)(x^2+xy+y^2) which is what you started with :)
75% of 56 is .75 * 56
.75 * 56 = 42
Because you are decreasing, you subtract 42 from 56.
56 - 42 = 14
A 75% decrease of 56 books would leave 14 books.