Question

qual e o resultado {3x-2y=7{5x+3y=-20

Answer 1

Olá, Karolyny.

$\begin{cases}3x-2y=7\ \ (\times3)\\5x+3y=-20\ \ (\times2)\end{cases}\Rightarrow\begin{cases}9x-6y=21\\10x+6y=-40\end{cases}(+)\\\\\\\Rightarrow19x=-19\Rightarrow\boxed{x=-1}\\\\\text{Substituindo na primeira equa\c{c}\~ao:}\\\\3(-1)-2y=7\Rightarrow-2y=10\Rightarrow\boxed{y=-5}$