\(\overrightarrow{AB}=\left(3;-6\right)\), gọi \(M\left(x;y\right)\Rightarrow\overrightarrow{AM}=\left(x-1;y-3\right)\)
a/ \(MA=2MB\Rightarrow\overrightarrow{AM}=\frac{1}{3}\overrightarrow{AB}\)
\(\Rightarrow\left\{{}\begin{matrix}x-1=\frac{3}{3}\\y-3=-\frac{6}{3}\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}x=2\\y=1\end{matrix}\right.\) \(\Rightarrow M\left(2;1\right)\)
b/ \(MB=5MA\Rightarrow\overrightarrow{AM}=\frac{1}{6}\overrightarrow{AB}\)
\(\Rightarrow\left\{{}\begin{matrix}x-1=\frac{3}{6}\\y-3=-\frac{6}{6}\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}x=\frac{3}{2}\\y=2\end{matrix}\right.\) \(\Rightarrow M\left(\frac{3}{2};2\right)\)