Câu 2:Gọi $M\left\{ \begin{array}{l} p_1\\ n_1 \end{array} \right.$ $X\left\{ \begin{array}{l} p_2\\ n_2 \end{array} \right.$
Ta có :$\left\{ \begin{array}{l} 4p_1+2p_2+n_1+n_2=140\\ 4p_1+2p_2-(n_1+n_2)=44 \end{array} \right.$
$\Leftrightarrow 8p_1+4p_2=184(1)$
Lại có:$\left\{ \begin{array}{l} p_1+n_1-(p_2+n_2)=23\\ 2p_1+n_1-(2p_2+n_2)=34\end{array} \right.$
$\Leftrightarrow \left\{ \begin{array}{l} p_1-p_2+n_1-n_2=23\\ 2(p_1-p_2)+n_1-n_2=34 \end{array} \right.$
$\Leftrightarrow \left\{ \begin{array}{l} p_1-p_2=11(2)\\ n_1-n_2=12 \end{array} \right.$
Từ $(1) $ và $(2) \Rightarrow \left\{ \begin{array}{l} p1=19\\ p_2=8 \end{array} \right.$