（xy-x²）²÷(x-y)²/xy·x-y/x²

Question

（xy-x²）²÷(x-y)²/xy·x-y/x²

Answer 1

原式=[-x(x-y)]²*xy/(x-y)²*(x-y)/x²
=x²(x-y)²*xy/(x-y)²*(x-y)/x²
=x³y*(x-y)/x²
=xy-y²