Câu $1:$$\begin{cases}\frac{(P_{X_1}+N_{X_1})+(P_{X_2}+N_{X_2})}{2}=80 \\ P_{X_1}=P_{X_2}\\N_{X_2}-N_{X_1}=2 \end{cases}\Rightarrow \begin{cases}(P_{X_1}+N_{X_1})=79 \\ (P_{X_2}+N_{X_2})=91 \end{cases}\Rightarrow \begin{cases}A_{X_1}=79 \\ A_{X_2}=81 \end{cases}$
Câu $2:$
$*)(P_M+N_M)+35=76\Rightarrow P_M+N_M=41$
$*)\begin{cases}N_M-P_M=3 \\ P_M-P_X=6\\N_M+N_X=36\\P_M+N_M=41 \end{cases}\Rightarrow \begin{cases}P_M=19 \\ N_M=22\\P_X=13\\N_X=14 \end{cases}\Rightarrow \begin{cases}A_M=41 \\ A_X=27 \end{cases}$