we can't solve for all solutions, but we can solve for x or y (infinite solutions)
remember that we can do anything to an equation as long as we do it to both sides
solving for x
2x-y=-11
add y to both sides
2x=y-11
divide by 2
x=(y-11)/2
solving for y
2x-y=-11
subtract 2x from both sides
-y=-2x-11
multiply -1
y=2x+11