Question

Calcule as raízes da equação -y²+7y=0

Answer 1

Propriedade do produto nulo

$\large\boxed{\boxed{\mathsf{A.B=0\Leftrightarrow~A=0~ou~B=0}}}$

$\mathsf{-{y}^{2}+7y=0\times(-1)}\\\mathsf{{y}^{2}-7y=0}\\\mathsf{y(y-7)=0}\\\mathsf{y=0}\\\mathsf{y-7=0\to~y=7}\\\\\huge\boxed{\boxed{\mathsf{s=\{0,7\}}}}$