Question

Simplificando a expressão (9-x^2)/(x^2-5x+6), com x diferente de 2, obtém-se

Answer 1

$\frac{9-x^2}{x^2-5x+6}=\frac{(3+x)\cdot(3-x)}{(x-3)\cdot(x-2)}=\frac{(3+x)\cdot(-1)\cdot (-3+x)}{(x-3)\cdot(x-2)}=\frac{(3+x)\cdot(-1)\cdot (x-3)}{(x-3)\cdot(x-2)}\\ \\=\frac{(3+x)\cdot(-1)}{x-2}=\frac{-3-x}{x-2}$