| $$ \begin{aligned}4x^3y+2xy^2-6xy+4xy^3+12x^2y^2& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}4x^3y+12x^2y^2+4xy^3+2xy^2-6xy\end{aligned} $$ | |
| ① | Combine like terms: $$ 4x^3y+12x^2y^2+4xy^3+2xy^2-6xy = 4x^3y+12x^2y^2+4xy^3+2xy^2-6xy $$ |