Question

计算： [(x+y)(x-y)-(x-y)^2+2y(x-y)]/(-2y)

Answer 1

解： [(x+y)(x-y)-(x-y)^2+2y(x-y)]/(-2y）
=[x^2-y^2-(x^2-2xy+y^2)+2xy-2y^2]/(-2y)
=[4xy-4y^2]/(-2y)
=2y-2x

Answer 2

原式=(x-y)[(x﹢y)-(x-y)﹢2y] ∕ (-2y)=(x-y)4y ∕ (-2y)=-2(x-y)=2y-2x

Answer 3

={(X-Y)[X+Y-(X-Y)+2Y]}/(-2Y)
=[4Y(X-Y)]/(-2Y)
=-2Y(X-Y)
=-2XY+2Y^2

这种题目不难，一步一步慢慢来就行了

Answer 4

[(x+y)(x-y)-(x-y)²+2y(x-y)]/(-2y)
=(x-y)[(x+y)-(x-y)+2y]/(-2y)
=(x-y)(x+y-x+y+2y)/(-2y)
=4y(x-y)/(-2y)
=-2(x-y)
=2y-2x

Answer 5

=[x^2-y^2-(x^2-2xy+y^2)+2xy-2y^2]/(-2y)
=(x^2-y^2-x^2+2xy-y^2+2xy-2y^2)/(-2y)
=(4xy-4y^2)/(-2y)
=-2x+2y