| $$ \begin{aligned}2a^2-8a^2+5a^2-11a^2& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-12a^2\end{aligned} $$ | |
| ① | Combine like terms: $$ \color{blue}{2a^2} \color{red}{-8a^2} + \color{green}{5a^2} \color{green}{-11a^2} = \color{green}{-12a^2} $$ |