$$ \begin{aligned}4a^3+6a^2b^3+6a^3+9a^2b^3& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}15a^2b^3+10a^3\end{aligned} $$ | |
① | Combine like terms: $$ \color{blue}{4a^3} + \color{red}{6a^2b^3} + \color{blue}{6a^3} + \color{red}{9a^2b^3} = \color{red}{15a^2b^3} + \color{blue}{10a^3} $$ |