Đáp án:
$\begin{array}{l}
{\left( {{a^3} + a} \right)^2} = {a^6} + {\left( {{a^3} - a} \right)^2}\\
\Rightarrow {a^2}{\left( {{a^2} + 1} \right)^2} = {a^6} + {a^2}{\left( {{a^2} - 1} \right)^2}\\
\Rightarrow {a^4} + 2{a^2} + 1 = {a^4} + {a^4} - 2{a^2} + 1\\
\Rightarrow {a^4} - 4{a^2} = 0\\
\Rightarrow {a^2} = 4\\
\Rightarrow a = 2\\
\Rightarrow \left\{ \begin{array}{l}
CD = {a^3} = 8\\
CR = {a^3} - a = 6\\
ĐC = {a^3} + a = 10
\end{array} \right.
\end{array}$
