Step-by-step explanation:
Given
9x + 3y = - 6..........equation 1
9x + 7y = 10 ..........equation 2
Now subtracting both equations we get
9x + 3y = -6
9x + 7y = 10
- - = -
-4y = -16
Therefore y = 4
Now putting y = 4 in equation 1
9 * 4 + 3y = -6
36 + 3y = -6
3y = -6- 36
3y = -42
Therefore y = -14
