You can put this solution on YOUR website! All you have to do to solve this problem is a little elimination. Since in one equation 1y is positive and in the other 1y is negative, it is easy to eliminate. Simply line x-y=-18 up to x+y=-9 and add the expression and their answers. You should have gotten . Then divide each side by two and get . Then plug x in the first equation and end up with y=4.5. . Your solutions for x and y are the coordinates of the point of intersection of the two lines.