Đáp án:
\[\begin{array}{l}
f,\,\,\,\,5\\
g,\,\,\,\,\,\,\frac{{12}}{{31}}
\end{array}\]
Giải thích các bước giải:
\(\begin{array}{l}
f,\\
\frac{{\left( { - 7} \right).3 + 4.\left( { - 6} \right)}}{{\left( { - 5} \right).3 + 2.3}} = \frac{{\left( { - 7} \right).3 + 4.\left( { - 2} \right).3}}{{\left( { - 5} \right).3 + 2.3}} = \frac{{3.\left( { - 7 - 8} \right)}}{{3\left( { - 5 + 2} \right)}} = \frac{{ - 15}}{{ - 3}} = 5\\
g,\\
\frac{{121212}}{{313131}} = \frac{{12.10101}}{{31.10101}} = \frac{{12}}{{31}}
\end{array}\)