Giải các phương trình:
a.$\frac{4x+5}{x-1}$ + $\frac{2x-1}{x+1}$ =6
b.$\frac{x+2}{x-3}$ + $\frac{x-2}{x+3}$ = $\frac{2(x^2+6)}{x^2-9}$
c.$\frac{1}{x-2}$ +3 = $\frac{3x-2}{x+2}$
d.$\frac{8}{x+1}$ + $\frac{1}{x-1}$ = $\frac{9}{x}$
e.(4x+1)($\frac{3x+7}{3-5x}$+1) = (x-4)($\frac{3x+7}{5x-3}$-1)
f.($x^{2}$+3x+1)($\frac{4x-3}{3x+1}$+2) = (4x+7)($\frac{4x-3}{3x+1}$+2)