| $$ \begin{aligned}4x^3-2x^2+3x^3+x^2& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}7x^3-x^2\end{aligned} $$ | |
| ① | Combine like terms: $$ \color{blue}{4x^3} \color{red}{-2x^2} + \color{blue}{3x^3} + \color{red}{x^2} = \color{blue}{7x^3} \color{red}{-x^2} $$ |