Question
Answer
$$3i\cdot(2+i)=6i-3$$
Explanation
Tap the blue circles to see an explanation.
| $$ \begin{aligned}3i\cdot(2+i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}6i+3i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}6i-3\end{aligned} $$ | |
| ① | Multiply $ \color{blue}{3i} $ by $ \left( 2+i\right) $ $$ \color{blue}{3i} \cdot \left( 2+i\right) = 6i+3i^2 $$ |
| ② | $$ 3i^2 = 3 \cdot (-1) = -3 $$ |
This page was created using
Complex Expression calculator