Respuesta :

3 - B  

4 - A

5 - A

6. x = y + 6
2x + y = 0
2(y+6) + y = 0
2y + 12 + y = 0
3y = -12
y = -4

x = 6 - 4 = 2

Solution would be: (2, -4) [ Option B ]

7) 3x + y = -8
  2x - y = 3

Add both equations, 
5x = -5
x = -1

Now, 2(-1)  - y = 3
-y = 3 + 2
y = -5

Solution would be: (-1, -5) [ Option A ]

Hope this helps!