2x-2y/y * 3y^2/x^2-y^2
2(x-y)/y * 3y^2/(x-y)(x+y)
6y/x+y
a^2-b^2/5a^2 * a/3a+3b
(a-b)(a+b)/5a^2 * a/3(a+b)
a-b/15a
a+x/a : ax+x^2/a^2
a+x/a * a^2/x(a+x)
a/x
ac-a^2/c^2 : c-a/c
ac-a^2 /c^2 * c/c-a
a(c-a)/c^2 * c/c-a
a/c
x^2-y^2/2xy * 2y/x-y
(x-y)(x+y)/2xy * 2y/x-y
2xy^2/2xy
y
4ac/a^2-c^2 * a+c/ac
4ac/(a-c)(a+c) * a+c/ac
4/a-c
