Given a = {x, XY. X minus y} B = {0, absolute value x, y} and a = B, find x, y RT has been calculating for a long time, but I can't work it out

Given a = {x, XY. X minus y} B = {0, absolute value x, y} and a = B, find x, y RT has been calculating for a long time, but I can't work it out

In a, X is not equal to XY, so x is not equal to 0. If xy = 0, then y = 0 is impossible, because there are 0 in B, and if y = 0, then there are two identical elements, so X-Y = 0, x = y, because the absolute value x is not equal to y, so y = 0