Question

2x + y =8
x + y =6

2x + y =13
5x - 2y =1

Answer 1

|2x + y = 8
|-x -y = -6

2x -x + y - y = 8 - 6
x = 2

(Para descobrir o y)
X + y = 6
2 + y = 6
y = 6 - 2
y = 4


|4x + 2y = 26
|5x - 2y = 1

4x + 5x + 2y - 2y = 26 + 1
9x = 27
x = 3

(Para descobrir o y)

2x + y = 13
2.3 + y = 13
6 + y = 13
y = 13 - 6
y = 7

Answer 2

1- usando soma
2x+Y=8
X+Y=6(-1)
---------
2x+Y=8
-x-y=-6
----------
X=2.
2.2+Y=8 4+Y=8. Y=8-4=4

2- usando substituição
2x+Y=13
5x-2y=1
-----------
Y=13-2x
5x -2(13-2x)=1
5x -26+4x=1
9x=26+1=27/9=3. X=3
2.3+Y=13
Y=13-6=7. Y=7