| $$ \begin{aligned}5ab+3ab-2ab+4a& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}6ab+4a\end{aligned} $$ | |
| ① | Combine like terms: $$ \color{blue}{5ab} + \color{red}{3ab} \color{red}{-2ab} +4a = \color{red}{6ab} +4a $$ |