$$ \begin{aligned}\frac{\sqrt{5}}{3}\sqrt{15}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{5\sqrt{3}}{3}\end{aligned} $$ | |
① | $$ \color{blue}{ \sqrt{5} } \cdot \sqrt{15} = 5 \sqrt{3} $$$$ \color{blue}{ 3 } \cdot 1 = 3 $$ |