You can use the process elimination to solve. In other words, subtract or add the equations like normal.
5x + 2y = -15
+ 2x - 2y = -6
Because there is a 2y and -2y, we can add both equations to eliminate the y so that we can figure out what x is:
5x + 2x = 7x
2y + (-2y) = 0
-15 + (-6) = -21
We now have 7x = -21
Divide all by 7 to get x = -3
Plug in -3 to any of the two equations. I will use the second equation:
2(-3) - 2y = -6
-6 - 2y = -6
-2y = 0
y = 0
This means that the solution to the system of equations is (-3, 0) in the form of (x, y).
