Question

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Answer 1

$(x^2 - xy) : \dfrac{x^2 - y^2}{2y} = x(x - y) \cdot \dfrac{2y}{(x - y)(x + y)} = \dfrac{2xy(x - y)}{(x - y)(x + y)} = \\ \\ \dfrac{2xy}{x+y}$

Answer 2

(x²-xy):(x²-y²)/2y=x(x-y)*2y/(x-y)(x+y)=2xy/(x+y)