a: \(\left(3x-2\right)\cdot\left(\dfrac{2}{7}\left(x+3\right)-\dfrac{4x-3}{5}\right)=0\)
\(\Leftrightarrow\left(3x-2\right)\left(\dfrac{2}{7}x+\dfrac{6}{7}-\dfrac{4}{5}x+\dfrac{3}{5}\right)=0\)
\(\Leftrightarrow\left(3x-2\right)\left(-\dfrac{18}{35}x+\dfrac{51}{35}\right)=0\)
=>x=2/3 hoặc x=51/18=17/6
b \(\left(3.3-11x\right)\left(\dfrac{7x+2}{5}+\dfrac{2\left(1-3x\right)}{3}\right)=0\)
\(\Leftrightarrow\left(-10x+3\right)\left(21x+6+10-30x\right)=0\)
\(\Leftrightarrow\left(-10x+3\right)\left(-9x+16\right)=0\)
=>x=3/10 hoặc x=16/9
c: \(\dfrac{3}{7x-1}=\dfrac{1}{7x\left(3x-7\right)}\)
=>21x(3x-7)=7x-1
\(\Leftrightarrow63x^2-154x+1=0\)
\(\text{Δ}=\left(-154\right)^2-4\cdot63=23464\)
Vì Δ>0 nên phương trình có hai nghiệm phân biệt là:
\(\left\{{}\begin{matrix}x_1=\dfrac{154-\sqrt{23464}}{126}\\x_2=\dfrac{154+\sqrt{23464}}{126}\end{matrix}\right.\)
