Question

решите систему 8y-x=4 и 2x-21y=2

Answer 1

$left { {{-x+8y=4} atop {2x-21y=2}} right. left { {{-2x+16y=8} atop {2x-21y=2}} right.$
-5y=10
y=-2
8*(-2)-x=4
x=-20                         (-20;-2)