| $$ \begin{aligned}(9+5)x^3& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}14x^3\end{aligned} $$ | |
| ① | Combine like terms: $$ \color{blue}{9} + \color{blue}{5} = \color{blue}{14} $$ |