Question

化简分式计算①、(x+y)*x^2/x^2-y^2+y^2/x-y-(2x^2y-2xy^2)/(x^2-2xy+y^2

Answer 1

①、(x+y)*x^2/x^2-y^2+y^2/x-y-(2x^2y-2xy^2)/(x^2-2xy+y^2)

=x^2/(x-y)+y^2/(x-y)-2xy(x-y)/(x-y)^2

=(x^2+y^2)/(x-y)-2xy/(x-y)

=(x^2+y^2-2xy)/(x-y)

=x-y

②、m/m-n-n/m+n+2mn/m^2-n^2

={m(m+n)-n(m-n)}/(m^2-n^2)+2mn/(m^2-n^2)

=(m^2+n^2+2mn)/(m+n)(m-n)

=(m+n)/(m-n)