Đáp án:
$\begin{array}{l}
a)A = \left( {2x - 3} \right)\left( {4{x^2} + 6x + 9} \right)\\
- \left( {1 + 2x} \right)\left( {1 - 2x + 4{x^2}} \right)\\
= {\left( {2x} \right)^3} - {3^3} - \left( {{1^3} + 8{x^3}} \right)\\
= 8{x^3} - 27 - 1 - 8{x^3}\\
= - 28\\
b)B = \left( {2x - 1} \right)\left( {1 + 2x} \right)\left( {1 + 4{x^2}} \right)\\
- 2x\left( {2x - 1} \right)\left( {4{x^2} + 2x + 1} \right)\\
= \left( {4{x^2} - 1} \right)\left( {1 + 4{x^2}} \right) - 2x\left( {8{x^3} - 1} \right)\\
= 16{x^4} - 1 - 16{x^4} + 2x\\
= 2x - 1\\
= 2.\left( { - 1001} \right) - 1\\
= - 2003\\
c)C = {x^3} + 0,3{x^2} + 0,03x\\
= 0,{9^3} + 0,3.0,{9^2} + 0,03.0,9\\
= 0,999\\
d)D = {x^4} - 2{x^3} + 3{x^2} - 2x + 2\\
= {x^4} - {x^3} - {x^3} + {x^2} + 2{x^2} - 2x + 2\\
= {x^2}.\left( {{x^2} - x} \right) - x\left( {{x^2} - x} \right) + 2\left( {{x^2} - x} \right) + 2\\
= \left( {{x^2} - x} \right)\left( {{x^2} - x + 2} \right) + 2\\
= 3.\left( {3 + 2} \right) + 2\\
= 3.5 + 2\\
= 17\\
e)E = 27{x^3} + 27{x^2} + 10x - 999\\
= {\left( {3x} \right)^3} + 3.9{x^2}.1 + 3.3x + 1 + x - 1000\\
= {\left( {3x + 1} \right)^3} + x - 1000\\
= {\left( {3.33 + 1} \right)^3} + 33 - 1000\\
= {10^3} - 1000 + 33\\
= 33
\end{array}$
