Tìm x, biết:a) 5x + 12 = 8b) \(\frac{2}{3}x + \frac{1}{2} = \frac{1}{{10}}\)

* Hướng dẫn giải

\(\begin{array}{l}
a,\,\,5x + 12 = 8\\
\,\,\,\,\,\,\,\,\,\,\,5x = 8 - 12 =  - 4\\
\,\,\,\,\,\,\,\,\,\,\,x =  - 4:5 = \frac{{ - 4}}{5}
\end{array}\)

\(\begin{array}{l}
b,\,\,\frac{2}{3}x + \frac{1}{2} = \frac{1}{{10}}\\
\frac{2}{3}x = \frac{1}{{10}} - \frac{1}{2}\\
x = \frac{{ - 2}}{5}
\end{array}\)