# How do you simplify 7i*3i(-8-6i)?

Sep 8, 2016

$168 + 126 i$

#### Explanation:

The first step is to multiply 7i and 3i together.

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

$\Rightarrow 7 i \times 3 i = 21 {i}^{2} = - 21$

$\Rightarrow - 21 \left(- 8 - 6 i\right) = 168 + 126 i$