约分与通分
约分:
ac/2bc
xy^2/(x+y)y
(x+y)^2/x^2+xy
(x-y)^2/x^2-y^2
通分:
ab/x与bc/y
bd/2c与4b^2/3ac
a(x+2)/x与b(x+2)/y
(x+y)^2/2xy与x^2-y^2/x