| $$ \begin{aligned}6x^2y-21y^2w+24xw& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-21wy^2+6x^2y+24wx\end{aligned} $$ | |
| ① | Combine like terms: $$ -21wy^2+6x^2y+24wx = -21wy^2+6x^2y+24wx $$ |