Answer:
Q = -6
Explanation:
To find the answer to this, you first must multiply the first function by 2:
2 x (x - 3y = 4)
2x - 6y = 8
Which then means that the second function is the same. This means that to find Q you need to find the number that changed +Qy into -6:
2x - 6y = 8
2x + Qy = 8
The 2x's cancel out, and then remove the equals and the 8:
-6y = Qy
So Q must be -6
Hope this helps!