Question

qual é o resutado da conta 4x +2y = 20 x-y=10

Answer 1

$\left \{ {{4x-2y=20} \atop {x-y=10}} \right. \\ x=10+y \\ 4*(10+y)-2y=20 \\ 40+4y-2y=20 \\ 2y=20-40 \\ y= -\frac{20}{2} y=-10 \\ \\ x=10+(-10) \\ x=10-10 \\  x=0$