y=11+4x
Can be rearranged to:
y-4x=11
Then you put them on top of each other (like simultaneous equations):
y-4x=11
2y+3x=0
We have to make either the y or x in both equations be the same. So the easiest way would be to times the first equations by 2 to have both equations have 2y:
2y-8x=22
2y+3x=0
So then you take them away to make:
-11x=-22
You can remove the - as both side have - which makes:
11x=22
Then you just simplify to make
x=2
You put that back into one of the equations:
y=11+(4x2)
y=11+8
y=19
So the answer is x=2 and y=19