$\begin{array}{l} \,\,\,\,\left( {{x^2} - 2x} \right)\left( {{x^2} + 4x + 3} \right) - 24\\ = x\left( {x - 2} \right)\left( {x + 1} \right)\left( {x + 3} \right) - 24\\ = x\left( {x + 1} \right)\left( {x - 2} \right)\left( {x + 3} \right) - 24\\ = \left( {{x^2} + x} \right)\left( {{x^2} + x - 6} \right) - 24\\ = {\left( {{x^2} + x} \right)^2} - 6\left( {{x^2} - x} \right) - 24\\ = {\left( {{x^2} + x} \right)^2} - 6\left( {{x^2} - x} \right) + 9 - 33\\ = {\left( {{x^2} + x - 3} \right)^2} - 33\\ = \left( {{x^2} + x - 3 - \sqrt {33} } \right)\left( {{x^2} + x - 3 + \sqrt {33} } \right) \end{array}$
Xin hay nhất !
