3a-3b/10ab*25a^b3/a^-b^= x^-4y^/x^+2xy+y^/x+2y/2x^+2xy
问题描述：
3a-3b/10ab*25a^b3/a^-b^= x^-4y^/x^+2xy+y^/x+2y/2x^+2xy
(3a-3b)/(10ab)*(25a^b3)/(a^-b^)=
(x^-4y^)/(x^+2xy+y^)/(x+2y)/(2x^+2xy)=
答
1.
=3(a-b)/(10ab)*(25a^2 b^3)/((a+b)(a-b))
=15/2*(a b^2)/(a+b)
2.
=(x+2y)(x-2y)/(x+y)^2*2x(x+y)/(x+2y)
=2x(x-2y)/(x+y)