Trừ phân thức: a) x^2 + y^2/(x - y)^3 - 2xy/(x - y)^3. b) x^2 + 25y^2/x^2 - 25y^2 - 10xy/x^2 - 25y^2

Trừ phân thức:
a) x^2 + y^2/(x - y)^3 - 2xy/(x - y)^3.
b) x^2 + 25y^2/x^2 - 25y^2 - 10xy/x^2 - 25y^2.
c) 3x/5x + 5y - x/10x - 10y.
d) 1/x - 3 - 3/2x + 6 - x/2x^2 - 12x + 18.
e) (x^2 + 1) - x^4 - 3x^2 - 4/x^2 + 1.
f) 1/3x - 2 - 4/3x + 2 - 3x - 6/4 - 9x^2.
g) 4x^2 - 3x + 5/x^3 - 1 - 1 - 2x/x^2 + x + 1 - 6/x - 1.
h) 5/x + 1 - 10/x - x^2 - 1 - 2/4x^2 - 1.
i) 2/2x + 1 - 1/2x - 1 - 2/4x^2 - 1.