Đáp án:
$\begin{array}{l}
x = 2;\left| y \right| = 1 \Rightarrow \left[ \begin{array}{l}
y = 1\\
y = - 1
\end{array} \right.\\
B = {x^3}\left( {{x^2} - {y^2}} \right) + {y^2}\left( {{x^3} - {y^3}} \right)\\
+ Khi:x = 2;y = 1\\
\Rightarrow B = {2^3}.\left( {{2^2} - {1^2}} \right) + {1^2}\left( {{2^3} - {1^3}} \right)\\
= 8.\left( {4 - 1} \right) + 1.\left( {8 - 1} \right)\\
= 8.3 + 7\\
= 31\\
+ Khi:x = 2;y = - 1\\
\Rightarrow B = {2^3}.\left( {{2^2} - {{\left( { - 1} \right)}^2}} \right) + {\left( { - 1} \right)^2}.\left( {{2^3} - {{\left( { - 1} \right)}^3}} \right)\\
= 8.\left( {4 - 1} \right) + 1.\left( {8 + 1} \right)\\
= 8.3 + 9\\
= 33
\end{array}$
Vậy B=31 hoặc B=33
