Mathematic Problems
a3-b3a-b+ab·a-ba-b2=1a>0 ; b>0 
a=x b=y
x3-y3x-y+xy·x-yx2-y22=1
x3-y3x-y+xy·x-yx2-y22=1
x-yx2-xy+y2x-y+xy·x-yx-yx+y2=1
x2+y2·1x+y2=1
1=1
1=1