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