Question

resolva o sistema {2x+4y=34
{2x-2y=4

Answer 1

$\Large\boxed{\begin{array}{l}\begin{cases}\sf 2x+4y=34\\\sf 2x-2y=4\cdot(2)\end{cases}\\\\\begin{cases}\sf 2x+\diagdown\!\!\!\!\!\!4y=34\\\sf4x-\diagdown\!\!\!\!\!\!4y=8\end{cases}\\\sf 6x=42\\\sf x=\dfrac{42}{6}\\\\\sf x=7\blue{\checkmark}\\\sf 2x-2y=4\div2\\\sf x-y=2\\\sf y=x-2\\\sf y=7-2\\\sf y=5\\\sf S=\{7,5\}\end{array}}$