| $$ \begin{aligned}6+8n^2+8n^2+3& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}16n^2+9\end{aligned} $$ | |
| ① | Combine like terms: $$ \color{blue}{6} + \color{red}{8n^2} + \color{red}{8n^2} + \color{blue}{3} = \color{red}{16n^2} + \color{blue}{9} $$ |