| $$ \begin{aligned}3\sqrt{72}\sqrt{96}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}144\sqrt{3}\end{aligned} $$ | |
| ① | $$ 3 \sqrt{6912} =
3 \sqrt{ 48 ^2 \cdot 3 } =
3 \sqrt{ 48 ^2 } \, \sqrt{ 3 } =
3 \cdot 48 \sqrt{ 3 } =
144 \sqrt{ 3 } $$ |