CE: $x+2y+1=0; E\in CE\Rightarrow E(-2t-1;t)$$\Rightarrow D(-4t-3;2t+2) \Rightarrow B (5+4t;-2t-2)$
mà $B\in BM \Rightarrow t=\frac{-4}{5}$
$\Rightarrow B(\frac{9}{5};\frac{-2}{5});D(\frac{1}{5};\frac{2}{5})$
$M=BM cắt CE \Rightarrow M(\frac{7}{5};\frac{-6}{5} ) \Rightarrow N(\frac{8}{5};\frac{-4}{5})$
$\Rightarrow pt AN:...;; pt DM:..$ từ đó suy ra tđ