# How do you multiply (-3+2i)(-3-4i)?

Sep 14, 2017

Just like any other polynomials....

#### Explanation:

...except any time you get a multiple of ${i}^{2}$, remove the $i$ and change the sign on the coefficient.

(-3 + 2i)(-3 - 4i) =

$\left(- 3 \cdot - 3\right) + \left(- 3 \cdot - 4 i\right) + \left(2 i \cdot - 3\right) + \left(2 i \cdot 4 i\right)$

$= 9 + 12 i - 6 i + 8 {i}^{2}$

$= 9 + 6 i - 8$

$= 1 + 6 i$

GOOD LUCK!