| $$ \begin{aligned}-2u^3(-4u^6)& \xlongequal{ }--8u^9 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}8u^9\end{aligned} $$ | |
| ① | Remove the parentheses by changing the sign of each term within them. $$ - \left(-8u^9 \right) = 8u^9 $$ |