Question

ok so on this practice test when you go to compass test A and do the 1st test on it... question A6 says the answer is A, http://www.highlands.edu/site/academic-support-compass-math-practice can some explain to me why the answer is not c????

Answer 1

starting with:
\[5y^3-125y\]
notice that you can factor out a 5y to get:
\[5y(y^2-25)\]
the stuff inside the parenthesis is the difference of two perfect squares, which means it can be further factored into:
\[5y(y-5)(y+5)\]
remember that the difference of squares rule says:
\[a^2-b^2 = (a-b)(a+b)\]