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