Đáp án:
f. \(\left[ \begin{array}{l}
x = - 1\\
x = \dfrac{5}{3}
\end{array} \right.\)
Giải thích các bước giải:
\(\begin{array}{l}
a.x = \dfrac{1}{3} + \dfrac{3}{7}\\
\to x = \dfrac{{16}}{{21}}\\
e.{\left( {x - \dfrac{2}{3}} \right)^3} = {\left( { - \dfrac{1}{3}} \right)^3}\\
\to x - \dfrac{2}{3} = - \dfrac{1}{3}\\
\to x = - \dfrac{1}{3} + \dfrac{2}{3}\\
\to x = \dfrac{1}{3}\\
b.\dfrac{1}{{4x}} = \dfrac{2}{5} - \dfrac{3}{4}\\
\to \dfrac{1}{{4x}} = - \dfrac{7}{{20}}\\
\to x = \dfrac{1}{4}:\left( { - \dfrac{7}{{20}}} \right)\\
\to x = - \dfrac{5}{7}\\
f.\left| {\dfrac{1}{3} - x} \right| = 1 + \dfrac{1}{3}\\
\to \left| {\dfrac{1}{3} - x} \right| = \dfrac{4}{3}\\
\to \left[ \begin{array}{l}
\dfrac{1}{3} - x = \dfrac{4}{3}\\
\dfrac{1}{3} - x = - \dfrac{4}{3}
\end{array} \right.\\
\to \left[ \begin{array}{l}
x = - 1\\
x = \dfrac{5}{3}
\end{array} \right.
\end{array}\)
