Question

Quanto da ( 1 + x )( 1 - x ) - ( 1 + x )² ?

Answer 1

(1+x)²=1+2x+x²

(1+x)(1-x)=1²-x²=1-x²

( 1 + x )( 1 - x ) - ( 1 + x )²=
=(1-x²)-(1+2x+x²)
=1-x²-1-2x-x²
=-2x²-2x
ou
=-2x(x+1)