分式的加减
(1)x-y分之3y-x的平方-xy分之2xy
=3y/(x-y)-2xy/(x^2-xy)
=3y/(x-y)-2y/(x-y)
=y/(x-y)
(2)b分之a-a分之b-ab分之a的平方+b的平方
=a/b-b/a-(a^2+b^2)/ab
=a^2/ab-b^2/ab-(a^2+b^2)/ab
=(a^2-b^2-a^2-b^2)/ab
=-2b^2/ab
=-2b/a
分式的加减
(1)x-y分之3y-x的平方-xy分之2xy
=3y/(x-y)-2xy/(x^2-xy)
=3y/(x-y)-2y/(x-y)
=y/(x-y)
(2)b分之a-a分之b-ab分之a的平方+b的平方
=a/b-b/a-(a^2+b^2)/ab
=a^2/ab-b^2/ab-(a^2+b^2)/ab
=(a^2-b^2-a^2-b^2)/ab
=-2b^2/ab
=-2b/a