For 11, we can subtract x from both sides for the first equation to get y=8-x, making the slope -1 for both equations and therefore making it parallel.
For 13, we can solve for y in the first equation by subtracting 14 from both sides and therefore getting 2x-14=y. For the next one, we can subtract 4x from both sides to get 10-4x=2y. Dividing both sides by 2, we get 10-2x=y. Since for the equations to be parallel they must be the same and for perpendicular they must be -1/(slope), this fits neither.
Using those two explanations, I implore you to solve the other two on your own!
