Solve the system by substitution.

2x+y=-11
3x-4=11

First isolate y in the first equation:

y = -2x - 11

Then substitute this into the second equation:

3x - 4 = 11
3x = 15
x = 5

Now substitute x back into y = -2x - 11:

y = -2(5) - 11
y = -10 - 11
y = -21

Therefore, the solution to the system of equations is x = 5 and y = -21.