\[\begin{array}{l}
g,{x^4} + {x^3} + {x^2} + x\\
= {x^3}\left( {x + 1} \right) + x\left( {x + 1} \right)\\
= \left( {x + 1} \right)\left( {{x^3} + x} \right)\\
= \left( {x + 1} \right)x\left( {{x^2} + 1} \right)\\
h,{x^3} + 2{x^2} - x - 2\\
= {x^2}\left( {x + 2} \right) - \left( {x + 2} \right)\\
= \left( {x + 2} \right)\left( {{x^2} - 1} \right)\\
= \left( {x + 2} \right)\left( {x - 1} \right)\left( {x + 1} \right)\\
i,{x^2} - xy - x + y\\
= x\left( {x - y} \right) - \left( {x - y} \right)\\
= \left( {x - y} \right)\left( {x - 1} \right)\\
J,xy + 4 - {x^2} + 2y\\
= \left( {xy + 2y} \right) - \left( {{x^2} - 4} \right)\\
= y\left( {x + 2} \right) - \left( {x - 2} \right)\left( {x + 2} \right)\\
= \left( {x + 2} \right)\left( {y - x + 2} \right)\\
k,2y + y - 2(x + 1)\\
= 3y - 2\left( {x + 1} \right)\\
l.2(x + y) + ay + ax\\
= 2\left( {x + y} \right) + a\left( {x + y} \right)\\
= \left( {x + y} \right)\left( {2 + a} \right)
\end{array}\]