Tap the blue circles to see an explanation.
| $$ \begin{aligned}-3i\cdot(4-i\cdot1.41421356)& \xlongequal{ }-3i\cdot(4-i) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}-(12i-3i^2) \xlongequal{ } \\[1 em] & \xlongequal{ }-(12i+3) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}-12i-3\end{aligned} $$ | |
| ① | Multiply $ \color{blue}{3i} $ by $ \left( 4-i\right) $ $$ \color{blue}{3i} \cdot \left( 4-i\right) = 12i-3i^2 $$ |
| ② | Remove the parentheses by changing the sign of each term within them. $$ - \left(12i+3 \right) = -12i-3 $$ |