What is the root of the polynomial equation x open paren x minus 2 close paren open paren x plus 3 close paren is equal to 18 ? Use a graphing calculator and a system of equations.

Substitute x = 3 into the left side: 3(3 − 2)(3 + 3) = 3 · 1 · 6 = 18. So x = 3 satisfies the equation, and the correct choice is 3.

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