Eliminate y to solve for x. plug in x into the second equation to solve for y

If your trying to get Y=mx + b the answer would be 1. Y= x+4 2. Y= -1/3x + 4/3

So u want to get rid of y right?
ok.. so these r the equations:
-x+y=4
x+3y=4

now the easiest way we can go is by multiplying the first equation by negative 3 to cancel out the y's
so it would look like this:
-3(-x+y=4) => 3x-3y=-12

no we can eliminate the y's
(3x-3y=-12) +(x+3y=4)   =   4x=-8

now divide by 4 so we can get x by itself

4x=8
x=2

we have x. plug in to 2nd equation to solve for y

(2)+3y=4
-2         -2
3y=2
y=2/3

hope that helps :)