$\begin{array}{l} 8)\\ \left( {x + 5} \right)\left( {{x^2} - 5x + 25} \right) - {\left( {2x + 1} \right)^3} + 7{\left( {x - 1} \right)^3} - 3x\left( {5 - 11x} \right)\\ = {x^3} + 125 - \left( {8{x^3} + 12{x^2} + 6x + 1} \right) + 7\left( {{x^3} - 3{x^2} + 3x - 1} \right) - 15x + 33{x^2}\\ = \left( {{x^3} + 7{x^3} - 8{x^3}} \right) + \left( {33{x^2} - 21{x^2} - 12{x^2}} \right) + \left( {21x - 6x - 15x} \right) + \left( {125 - 1 - 7} \right)\\ = 117 \end{array}$
