What is the solution to the system of equation?

Both equations are set equal to y. Set them equal to each other now:
y = -2x - 4
y = 2x + 4
-2x - 4 = 2x + 4
Now we solve by isolating x. Subtract 2x from both sides:
-2x - 4 = 2x + 4
-4x - 4 = 4
And add 4 to both sides:
-4x - 4 = 4
-4x = 8
Now divide both sides by -4:
-4x = 8
x = -2
Now we substitute x into one of the original equations and simplify:
y = 2x + 4
y = 2(-2) + 4
y = -4 + 4
y = 0
So our solution:
(-2, 0)