Question

（xy-x²）÷[（x²-2xy+y²）÷xy]*[(x-y)÷x²]

Answer 1

（xy-x2）÷[（x2-2xy+y2）÷xy]*[(x-y)÷x2]=x（y-x）÷[（x-y）2÷xy]*[(x-y)÷x2]=x(y-x)*[1/（x2-2xy+y2）]*(1/xy)]*[(x-y)(1/x2)]=-1