Okay so first you "substitute" 3x for y in the other equation so it looks like this 3x=-x+4..... Then you solve for x by adding x to the other side so it's 4x= 4 then you divide by 4 and get x= 1...... Then you have to find y so you pull x into one equation like this y= 3*1 so y=3 So the final answer is (1,3)