Giải thích các bước giải:
Ta có:
\(\begin{array}{l}
c,\\
\left( {2x - 3} \right)\left( {{x^3} - {x^2} + 2} \right)\\
= 2{x^4} - 2{x^3} + 4x - 3{x^3} + 3{x^2} - 6\\
= 2{x^4} - 5{x^3} + 3{x^2} + 4x - 6\\
d,\\
\left( {2 + 1} \right)\left( {{2^2} + 1} \right)\left( {{2^4} + 1} \right).....\left( {{2^{256}} + 1} \right)\\
= \left( {2 - 1} \right).\left( {2 + 1} \right)\left( {{2^2} + 1} \right)\left( {{2^4} + 1} \right).....\left( {{2^{256}} + 1} \right)\\
= \left( {{2^2} - 1} \right).\left( {{2^2} + 1} \right)\left( {{2^4} + 1} \right).....\left( {{2^{256}} + 1} \right)\\
= \left( {{2^4} - 1} \right)\left( {{2^4} + 1} \right).....\left( {{2^{256}} + 1} \right)\\
= \left( {{2^{256}} - 1} \right)\left( {{2^{256}} + 1} \right)\\
= {2^{512}} - 1
\end{array}\)
