Đáp án:
$\displaystyle \begin{array}{{>{\displaystyle}l}} a.\ x=\frac{38}{21}\\ b.\ x=\pm 2 \end{array}$
Giải thích các bước giải:
$\displaystyle \begin{array}{{>{\displaystyle}l}} a.\ 1\frac{1}{2} :( 3x-2) =\frac{1}{12} :\frac{4}{21}\\ \Leftrightarrow \frac{3}{2} .\frac{1}{3x-2} =\frac{7}{16}\\ \Leftrightarrow \frac{1}{3x-2} =\frac{7}{24}\\ \Leftrightarrow 3x-2=\frac{24}{7}\\ \Leftrightarrow x=\frac{38}{21}\\ b.\ \frac{2x+1}{5} =\frac{3}{2x-1} ;\ ĐKXĐ:x\neq \frac{1}{2}\\ \Leftrightarrow 4x^{2} -1=15\\ \Leftrightarrow 4x^{2} =16\\ \Leftrightarrow x^{2} =4\Leftrightarrow x=\pm 2 \end{array}$
