$$ \begin{aligned}-5-5i-5-10i& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-15i-10\end{aligned} $$ | |
① | Combine like terms: $$ \color{blue}{-5} \color{red}{-5i} \color{blue}{-5} \color{red}{-10i} = \color{red}{-15i} \color{blue}{-10} $$ |