# How do you multiply (2-6i)(7+7i)(3+3i)?

Feb 20, 2017

$252 + 84 i$

#### Explanation:

Multiply the first 2 factors and then multiply the result by the third factor.

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

Using the FOIL method to distribute.

$\Rightarrow \left(2 - 6 i\right) \left(7 + 7 i\right)$

$= 14 + 14 i - 42 i - 42 {i}^{2}$

$= 56 - 28 i$

Now multiply this product by the third factor.

$\Rightarrow \left(56 - 28 i\right) \left(3 + 3 i\right)$

$= 168 + 168 i - 84 i - 84 {i}^{2}$

$= 252 + 84 i$