What is the solution of the following system of equations?
2x + y = -7
-3x - 2y = 10

the solution is    (-4, -3)

Step-by-step explanation:

Multiply the first equation by 2.  This produces 4x + 2y = -14.

Now combine this result with the second equation:

4x + 2y = -14

-3x - 2y = 10

 x          = -4

Subbing -4 for x in the first equation yields 2x - 4 = -7, or 2x = -3.  

Then x = -3/2, and the solution is    (-4, -3)