Respostas

2013-11-05T13:00:34-02:00
(x+b).(x-b)=x.(x-b^3)

x^2-b^2=x^2-x.b^3

x^2-x^2-b^2=-x.b^3

-b^2=-x.b^3

\frac{-b^2}{b^3}=-x

\frac{-b^2}{b^2.b}=-x

\frac{-1}{1.b}=-x

\frac{-1}{b}=-x

Multiplicando os dois lados por (-1), teremos:

\frac{-1}{b}.(-1)=-x.(-1)

\frac{1}{b}=x

x=\frac{1}{b}