| $$ \begin{aligned}-8x\cdot(-8)& \xlongequal{ }--64x \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}64x\end{aligned} $$ | |
| ① | Remove the parentheses by changing the sign of each term within them. $$ - \left(-64x \right) = 64x $$ |