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) \(\dfrac{3x-1}{x-1}-\dfrac{2x+5}{x+3}+\dfrac{4}{x^2+2x-3}=1\)
b: \(\Leftrightarrow\dfrac{2}{\left(x+7\right)\left(x-3\right)}=\dfrac{3x+21}{\left(x-3\right)\left(x+7\right)}\)
=>3x+21=2
=>x=-19/3
d: \(\Leftrightarrow\left(2x+1\right)^2-\left(2x-1\right)^2=8\)
\(\Leftrightarrow4x^2+4x+1-4x^2+4x-1=8\)
=>8x=8
hay x=1