## Intermediate Algebra: Connecting Concepts through Application

7x$^3$-28x =7x(x$^2$-4) Inside the parenthesis is a difference of squares. If the square root of the first term is a and the square root of the second term is b, the factorization is (a+b)(a-b). $\sqrt {x^2}$=x and $\sqrt {4}$=2. So the factorization is 7x(x+2)(x-2).