| $$ \begin{aligned}-\sqrt{1250}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-25\sqrt{2}\end{aligned} $$ | |
| ① | $$ - \sqrt{1250} =
- \sqrt{ 25 ^2 \cdot 2 } =
- \sqrt{ 25 ^2 } \, \sqrt{ 2 } =
- 25 \sqrt{ 2 }$$ |