Simplify (x - y + 1) - (x + y - 1)
well subtract the 'x' and 'y' .both are 1 .so its gonna be 1-1+1=1 and do the same with the other side which is gonna be 1 also .so its gonna be 1-1=0 .
x2+y2 -1x + yx -y +1y
