Rút gọn các biểu thức sau: d) − 3 x ( x + 2 ) ^2 + ( x + 3 ) ( x − 1 ) ( x + 1 ) − ( 2 x − 3 ) ^2 .

d) \( - 3x{\left( {x + 2} \right)^2} + \left( {x + 3} \right)\left( {x - 1} \right)\left( {x + 1} \right) - {\left( {2x - 3} \right)^2}\)

\( = - 3x\left( {{x^2} + 4x + 4} \right) + \left( {x + 3} \right)\left( {{x^2} - 1} \right) - \left( {4{x^2} - 12x + 9} \right)\)

\[ = - 3{x^3} - 12{x^2} - 12x + {x^3} - x + 3{x^2} - 3 - 4{x^2} + 12x - 9\]

\[ = - 2{x^3} - 13{x^2} - x - 12.\]