Đáp án:
$\begin{array}{l}
A = {\left( {2x + y} \right)^2}{\left( {2x - y} \right)^2}\\
= {\left[ {\left( {2x + y} \right)\left( {2x - y} \right)} \right]^2}\\
= {\left( {4{x^2} - {y^2}} \right)^2}\\
= 16{x^4} - 8{x^2}{y^2} + {y^4}\\
B = {\left( {3x + 2} \right)^2} + 2\left( {2 + 3x} \right)\left( {1 - 2y} \right) + {\left( {2y - 1} \right)^2}\\
= {\left( {3x + 2} \right)^2} - 2\left( {3x + 2} \right)\left( {2y - 1} \right) + {\left( {2y - 1} \right)^2}\\
= {\left( {3x + 2 - 2y + 1} \right)^2}\\
= {\left( {3x - 2y + 3} \right)^2}\\
C = {\left( {x - y} \right)^2} + 4xy\\
= {x^2} - 2xy + {y^2} + 4xy\\
= {x^2} + 2xy + {y^2}\\
= {\left( {x + y} \right)^2}\\
D = {\left( {6x - 2} \right)^2} + 4\left( {3x - 1} \right)\left( {2 + y} \right) + {\left( {y + 2} \right)^2}\\
= {\left( {6x - 2} \right)^2} + 2.\left( {6x - 2} \right)\left( {y + 2} \right) + {\left( {y + 2} \right)^2}\\
= {\left( {6x - 2 + y + 2} \right)^2}\\
= {\left( {6x + y} \right)^2}\\
E = {\left( {5x + 5} \right)^2} + 10\left( {x - 3} \right)\left( {1 + x} \right) + {x^2} - 6x + 9\\
= {\left( {5x + 5} \right)^2} + 2.\left( {5x + 5} \right).\left( {x - 3} \right) + {\left( {x - 3} \right)^2}\\
= {\left( {5x + 5 + x - 3} \right)^2}\\
= {\left( {6x + 2} \right)^2}
\end{array}$
