Question

Resolva as equações

2x - 7y = 12
- 2x + 5y = -20

2x - y = -2
x + 3y = 6

Answer 1

2x-7y=12
-2x +5y =-20
Corta os '2x'
-2y=-8
y=4
Valor de x
2x - 7.4 = 12
2x -28 = 12
2x = 40
x=20
2.20 + 7.4 = 12
40 - 28 = 12
12 = 12

2x - y = -2
x + 3y =6.(-2)
-2x -6y = -12
2x -y = -2
-7y=-14
y=2

2x -2 = -2
x=0