| $$ \begin{aligned}10b^8+3ab^8+c+9abc+4b^2+1+c+4ab^7+9b^2& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}3ab^8+4ab^7+10b^8+9abc+13b^2+2c+1\end{aligned} $$ | |
| ① | Combine like terms: $$ 10b^8+3ab^8+ \color{blue}{c} +9abc+ \color{red}{4b^2} +1+ \color{blue}{c} +4ab^7+ \color{red}{9b^2} = 3ab^8+4ab^7+10b^8+9abc+ \color{red}{13b^2} + \color{blue}{2c} +1 $$ |