# How do you multiply 6i(4-12i)?

Jul 23, 2016

72 + 24i

#### Explanation:

$\textcolor{b l u e}{\text{distribute the bracket}}$ in the usual way. That is, multiply each term inside the bracket by the 6i, outside.

$\Rightarrow \left(6 i \times 4\right) - \left(6 i \times 12 i\right) = 24 i - 72 {i}^{2}$ and simplify

$\textcolor{\mathmr{and} a n \ge}{\text{Reminder}} \textcolor{red}{| \overline{\underline{\textcolor{w h i t e}{\frac{a}{a}} \textcolor{b l a c k}{{i}^{2} = \sqrt{{\left(- 1\right)}^{2}} = - 1} \textcolor{w h i t e}{\frac{a}{a}} |}}}$

$24 i - 72 {i}^{2} = 24 i - 72 \left(- 1\right) = 24 i + 72$

$\Rightarrow 6 i \left(4 - 12 i\right) = 24 i + 72$