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 - 15/x^3+1.

​i) 2/2x+1 - 1/2x-1 - 2/4x^2-1.