$$ \begin{aligned}x+x^2+x^3+x^4+5+x^6& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}x^6+x^4+x^3+x^2+x+5\end{aligned} $$ | |
① | Combine like terms: $$ x^6+x^4+x^3+x^2+x+5 = x^6+x^4+x^3+x^2+x+5 $$ |