Question

Expand and simplify (x+3)(x-3)(3x+2)

Answer 1

I think it would be 3x³ + 2x² - 27 - 18

Answer 2

(x+3)(x-3) results in a product which is the difference of two squares: x^2 - 3^2.

Multiply this (x^2 - 3^2) by the third factor, (3x+2):

3x^3 - 9x + 2x^2 - 3^2*2, or, in descending order by powers of x,

3x^3 + 2x^2 - 9x - 18