$$ \begin{aligned}-\sqrt{54}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-3\sqrt{6}\end{aligned} $$ | |
① | $$ - \sqrt{54} =
- \sqrt{ 3 ^2 \cdot 6 } =
- \sqrt{ 3 ^2 } \, \sqrt{ 6 } =
- 3 \sqrt{ 6 }$$ |