{x+7y = 3
{ 5x-2y=22
x+7y=3 => x=3-7y
5x-2y=22 =>
5*(3-7y) - 2y=22 =>15-35y-2y=22
15-37y=22 =>37y=15-22 =>37y= - 7
y=-7/37
x=3-7y =>3-7*(-7/37) + 3+49/37 = >
x= 160/37
{x=160/37
{ y=-7/37