1. giải pt :
a) \(\dfrac{1}{x-3}+2=\dfrac{5}{x-1}+x\)
b)\(\dfrac{2}{x^2+4x-21}=\dfrac{3}{x-3}\)
c) \(\dfrac{1}{x^2+2x+3}+4=\dfrac{1}{x^2+1}\)
d) \(\dfrac{2x+1}{2x-1}-\dfrac{2x-1}{2x+1}=\dfrac{8}{4x^2-1}\)
e) \(\dfrac{3x-1}{x-1}-\dfrac{2x+5}{x+3}+\dfrac{4}{x^2+2x-3}=1\)