回復 71# nanpolend 的帖子
複選第10題
\(\begin{align}
& \log a=2+2x \\
& \log b=3+x \\
& \log a-2\log b=-4 \\
& \frac{a}{{{b}^{2}}}={{10}^{-4}} \\
& a={{\left( \frac{b}{100} \right)}^{2}}\in N \\
& \\
& 360<{{\left( \frac{b}{100} \right)}^{2}}<400 \\
& \frac{b}{100}=19 \\
& b=1900,a=361 \\
\end{align}\)
