Quy đồng mẫu thức các phân thức
a) \(\frac{3}{x^2-2x}\) ; \(\frac{4}{3x-6}\) ; \(\frac{4x+1}{x^2-x-2}\)
b) \(\frac{2m}{m^2-n^2}\) ; \(\frac{2n^2}{m^3-n^3}\)
c) \(\frac{x-z}{x^2+xy+xz+yz}\); \(\frac{x+z}{x^2+xy-xz-yz}\)
d) \(\frac{x}{2x^2+7x-15}\); \(\frac{x+2}{x^2+3x-10}\); \(\frac{1}{x+5}\)
e) \(\frac{x+1}{x-x^2}\); \(\frac{x+2}{2-4x+2x^2}\)