Question

Resolva o sistema abaixo 2 x-y=-1 x+3 y=10

Answer 1

$\left \{ {{2x-y=-1} \atop {x+3y=+10}} \right.$
$2x-y=-1$  ⇒ (×3)
$6x-3y=-3$
$\left \{ {{6x-3y=-3} \atop {x+3y=+10}} \right.$
$7x-0=7$
$x=1$
∴ $1+3y=10$
$3y=9$
$y=3$