Question

Resolver (7-r).7.(7-r)=335

Answer 1

Olá, Caio.

$(7-r)\cdot7\cdot(7-r)=335\Rightarrow\\\\(7-r)\cdot(7-r)=\frac{335}7\Rightarrow\\\\(7-r)\²=\frac{335}7\Rightarrow$

Extraindo a raiz de ambos os lados, temos:

$7-r=\pm\sqrt\frac{335}7\Rightarrow\\\\\boxed{r=7\pm\sqrt\frac{335}7}$