| $$ \begin{aligned}-8616x^3+119x+1119x^4& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}1119x^4-8616x^3+119x\end{aligned} $$ | |
| ① | Combine like terms: $$ 1119x^4-8616x^3+119x = 1119x^4-8616x^3+119x $$ |