Ans: A
$\begin{array}{rcl}
m & = & 7 – 3n \\
3n & = & 7 – m \\
n & = & \dfrac{7-m}{3}
\end{array}$
$\begin{array}{rcl}
m & = & 7 – 3n \\
3n & = & 7 – m \\
n & = & \dfrac{7-m}{3}
\end{array}$
Resources for HKDSE Mathematics
Resources for HKDSE Mathematics
