Giải thích các bước giải:
$\begin{array}{l}
f)x{\left( {xa - xb} \right)^2} + 125{\left( {b - a} \right)^2}\\
= x.{\left( {x\left( {a - b} \right)} \right)^2} + 125{\left( {a - b} \right)^2}\\
= {x^3}{\left( {a - b} \right)^2} + 125{\left( {a - b} \right)^2}\\
= {\left( {a - b} \right)^2}\left( {{x^3} + 125} \right)\\
= {\left( {a - b} \right)^2}\left( {{x^3} + {5^3}} \right)\\
= {\left( {a - b} \right)^2}\left( {x + 5} \right)\left( {{x^2} - 5x + 25} \right)\\
h){\left( {2 - x} \right)^2} + \left( {x - 2} \right)\left( {x + 3} \right) - \left( {4{x^2} - 1} \right)\\
= {\left( {x - 2} \right)^2} + \left( {x - 2} \right)\left( {x + 3} \right) - \left( {2x - 1} \right)\left( {2x + 1} \right)\\
= \left( {x - 2} \right)\left( {x - 2 + x + 3} \right) - \left( {2x - 1} \right)\left( {2x + 1} \right)\\
= \left( {x - 2} \right)\left( {2x + 1} \right) - \left( {2x - 1} \right)\left( {2x + 1} \right)\\
= \left( {2x + 1} \right)\left( {x - 2 - 2x + 1} \right)\\
= \left( {2x + 1} \right)\left( { - x - 1} \right)
\end{array}$
