| $$ \begin{aligned}9a+6b-3-12a-9b+6& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-3a-3b+3\end{aligned} $$ | |
| ① | Combine like terms: $$ \color{blue}{9a} + \color{red}{6b} \color{green}{-3} \color{blue}{-12a} \color{red}{-9b} + \color{green}{6} = \color{blue}{-3a} \color{red}{-3b} + \color{green}{3} $$ |