# Chapter 3 - Exponents, Polynomials and Functions - Chapter Test: 28

7x(x+2)(x-2)

#### Work Step by Step

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).

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