| $$ \begin{aligned}3(8\sqrt{3}-7)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}24\sqrt{3}-21\end{aligned} $$ | |
| ① | $$ \color{blue}{ 3 } \cdot \left( 8 \sqrt{3}-7\right) = \color{blue}{3} \cdot 8 \sqrt{3}+\color{blue}{3} \cdot-7 = \\ = 24 \sqrt{3}-21 $$ |