Question

Resolva o sistema.

obs: conta por favor

Answer 1

Ola ,
Multiplique 

$\left \{ {{x + y= 5/2} \atop {x - y/2=1}} \right. \\ \left \{ {{x + y= 5/2} \atop {x - y/2=1} (-1)} \right. \\ \left \{ {{x + y= 5/2} \atop {-x + y/2=-1}} \right. \\ Corta x com x \\ \\ \left \{ {{x + y= 5/2} \atop {y=-2}} \right. \\ Agora so substituir \\ \\ x + (-2).2 = 5 \\ x = 1 e \\ y = -2$