Question

Resolva os sistemas :

1) x+y= -1
3x-y=3

2) x+2y=7
4x-y=10

Answer 1

1) {x+y=-1
{3x-y=3
4x=2
x=2/4
x=1/2
3x-y=3
3.1/2-y=3
1,5-y=3
-y=3-1,5
-y=1,5.(-1)
y=-1,5
2) {x+2y=7
{4x-y=10
4x-y=10.(2)
{x+2y=7
{8x-2y=20
5x=17
x=17/5
x=3,4
x+2y=7
3,4+2y=7
2y=7-3,4
2y=3,6
y=3,6/2
y=1,8
3)