ABCD is a parallelogram. Find the values of x and y. Solve for the value of z, if z = x - y.
We have x+30+x-30=180 which becomes 2x=180 so x=90 and x+30=y+20 so x+10=y and y=100 so z=-10 since 90-100=-10 so we have \(\boxed{z=-10}\)
