Tap the blue circles to see an explanation.
$$ \begin{aligned}(3+4i)\cdot(1-i)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}3-3i+4i-4i^2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-4i^2+i+3\end{aligned} $$ | |
① | Multiply each term of $ \left( \color{blue}{3+4i}\right) $ by each term in $ \left( 1-i\right) $. $$ \left( \color{blue}{3+4i}\right) \cdot \left( 1-i\right) = 3-3i+4i-4i^2 $$ |
② | Combine like terms: $$ 3 \color{blue}{-3i} + \color{blue}{4i} -4i^2 = -4i^2+ \color{blue}{i} +3 $$ |