Question

$3x - y = 3 \\ x + y = - 1$

Answer 1

3x - y = 3

x + y = -1

4x = 2

x = 2/4

x = 1/2

x + y = - 1

1/2 + y = -1

1 + 2y / 2 = -1

1 + 2y = -2

2y = -2 - 1

2y = - 3

y = -3 / 2