Solve the following for the x and y values. x being 0 when solving for y, and vice versa.
question 1: x + y = 4

question 2: x - y = -3

It states your "X" will be zero when solving for "Y". So when solving for "Y" your equation would be; 0+y=4 Then you solve. Y=4 Then you do the same with the "X": X+0=4. Then you solve. X=4 It would end up being (4(x),4(y) ) Then do the same for the next problem.