Resposta :
a) [1,-4], [3,4] , [4,8]
b)x+y=8 (2)
x-2y=7
2x +2y = 16
x-2y=7 (corta o y e soma o restante)
3x=23
x=23/3
x+y=8
23/3 + y =8
y= 8 - 23/3
y=1/3
c) x+y=14
x-y=2
2x=16
x=8
x+y=14
8+y=14
y=14 - 8
y=6
4 b) x/3 +y = 4
x - y/3 = 8/3 ( 3)
x/3 + y = 4
3x - y =8
x/3 + 3x =12
10x=36
x=3,6
y=2,8
b)x+y=8 (2)
x-2y=7
2x +2y = 16
x-2y=7 (corta o y e soma o restante)
3x=23
x=23/3
x+y=8
23/3 + y =8
y= 8 - 23/3
y=1/3
c) x+y=14
x-y=2
2x=16
x=8
x+y=14
8+y=14
y=14 - 8
y=6
4 b) x/3 +y = 4
x - y/3 = 8/3 ( 3)
x/3 + y = 4
3x - y =8
x/3 + 3x =12
10x=36
x=3,6
y=2,8