How do you write (x + 7)(x – 3)(x – 2) in standard form?

1 Answer
Apr 18, 2016

=x^3+2x^2-29x+42

Explanation:

This is a long one, but an easy one once you know this property: (a+b)(c+d)=a(c+d)+b(c+d)=ab+ad+bc+bd.
First lets ignore the (x-2), and just expand the (x+7)(x-3)
(x+7)(x-3)(x-2)=(x-2)*(x+7)(x-3)

=(x-2)*(x^2-3x+7x-21)

=(x-2)*(x^2+4x-21)

=x(x^2+4x-21)-2(x^2+4x-21)

=x^3+4x^2-21x-2x^2-8x+42

=x^3+2x^2-29x+42