Question

 { {{5x-y=1} \ {7x+2y=-2}} 

Answer 1

$\left \{ {{5x-y = 1} \atop {7x+2y = -2 }} \right. <=> \left \{ {{-y=1-5x} \atop {---}} \right.<=> \left \{ {{y=-1+5x} \atop {7x+2(-1+5x)=-2}} \right.$ <=>

$\left \{ {{----} \atop {7x-2+10x=-2}} \right. <=> \left \{ {{----} \atop {17x=0}} \right. <=> \left \{ {{y=-1} \atop {x=0}} \right.$

Solução: x= 0 e Y= -1