Đoán đề: Chia đa thức

$\begin{array}{l} b)\left( {{x^3} + 1} \right):\left( {{x^2} - x + 1} \right)\\  = \left( {x + 1} \right)\left( {{x^2} - x + 1} \right):\left( {{x^2} - x + 1} \right)\\  = x + 1\\ c)\left( {{x^3} - {x^2} - 5x - 3} \right):\left( {x - 3} \right)\\  = \left[ {{x^3} - 3{x^2} + 2{x^2} - 6x + x - 3} \right]:\left( {x - 3} \right)\\  = \left( {x - 3} \right)\left( {{x^2} + 2x + 1} \right):\left( {x - 3} \right)\\  = \left( {{x^2} + 2x + 1} \right) = {\left( {x + 1} \right)^2}\\ d)\left( {{x^4} + {x^3} - 6{x^2} - 5x + 5} \right):\left( {{x^2} + x - 1} \right)\\  = \left[ {{x^2}\left( {{x^2} + x - 1} \right) - 5{x^2} - 5x + 5} \right]:\left( {{x^2} + x - 1} \right)\\  = \left( {{x^2} + x - 1} \right)\left( {{x^2} - 5} \right):\left( {{x^2} + x - 1} \right)\\  = {x^2} - 5 \end{array}$