Question

25) 3^-2 - 3^2 =

A) 1/9 B) -1/9

C) 80/9 D) -80/9

Answer 1

$3^{-2}~-~3^2~=\\\\\\=~\left(\frac{1}{3}\right)^2~-~9\\\\\\=~\frac{1^2}{3^2}~-~9\\\\\\=~\frac{1}{9}~-~9\\\\\\=~\frac{1\,.\,1~-~9\,.\,9}{9}\\\\\\=~\frac{1-81}{9}\\\\\\~=~\boxed{-\frac{80}{9}}$

Resposta: Letra (d)