Question

Me ajudem ai, ( obs : preciso das contas)
1) {x + Y = 11
{ x - 2y = -1
2) { 2x - y = -8
{x + 2y = 6
3) {Y = 2x + 1
{x + y = - 5

Answer 1

1) -x-y=-11
x-2y=-1
________
-3y=-12
y=-12/-3
y=+4

x+y=11
x+4=11
x=11-4
x=7. S={7,4}


2)4x-2y=-16
x+2y=6
__________
5x=-10
x= -10/5
x= -2

x+2y=6
-2+2y=6
2y=6+2
y=8/2
y=4. S={ -2,4}


3)-2x+y=1
2x-y=-1
x+y=-5
________
3x=-6
x=-6/3
x= -2

x+y=-5
-2+y=-5
y= -5+2
y= -3. S= { -2, -3}