Đáp án:
B
Giải thích các bước giải:
Ta có:
\[\begin{gathered}
{R_{td1}} = {R_1} + {R_2} = 36 \hfill \\
\frac{1}{{{R_{td2}}}} = \frac{1}{{{R_1}}} + \frac{1}{{{R_2}}} \Leftrightarrow {R_{td2}} = \frac{{{R_1}{R_2}}}{{{R_1} + {R_2}}} = 8 \Leftrightarrow \frac{{{R_1}{R_2}}}{{36}} = 8 \Rightarrow {R_1}{R_2} = 288 \hfill \\
\left\{ \begin{gathered}
{R_1} + {R_2} = 36 \hfill \\
{R_1}{R_2} = 288 \hfill \\
\end{gathered} \right. \Leftrightarrow \left\{ \begin{gathered}
{R_1} = 24\Omega \hfill \\
{R_2} = 12\Omega \hfill \\
\end{gathered} \right. \hfill \\
\end{gathered} \]