Official solution
Line is \[{x \over 3} + {y \over 1} = 1\]
\[ \Rightarrow \] x + 3y -- 3 = 0
Let Image of point (--1, --4) is (\[\alpha \], \[\beta \])
Hence, \[{{\alpha + 1} \over 1} = {{\beta + 4} \over 3} = - 2\left( {{{ - 1 - 12 - 3} \over {10}}} \right)\]
\[ \Rightarrow \] \[{{\alpha + 1} \over 1} = {{\beta + 4} \over 3} = {{16} \over 5}\]
\[ \Rightarrow \] \[\alpha \] = \[{{11} \over 5}\], \[\beta \] = \[{{28} \over 5}\]