Tap the blue circles to see an explanation.
$$ \begin{aligned}5ii-2i& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}5i^2-2i \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-5-2i \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}-2i-5\end{aligned} $$ | |
① | $$ 5 i i = 5 i^{1 + 1} = 5 i^2 $$ |
② | $$ 5i^2 = 5 \cdot (-1) = -5 $$ |
③ | Combine like terms: $$ -2i-5 = -2i-5 $$ |