Question

simplify
(6 + 3i)(6 − 3i)

Answer 1

Answer:

45

Step-by-step explanation:

(6 + 3i)(6 − 3i) =6 (6 − 3i)+ 3i(6 − 3i)

= 36 -18i +18i-9$i^{2}$

if $i^{2} =-1$

36 -18i +18i-9$i^{2}$ = 36-9(-1)

=36+9

=45

=36-9i^2

=6^2 - (3i)^2

Answer 2

Answer:

$\displaystyle 45$

Step-by-step explanation:

$\displaystyle (6 + 3i)(6 - 3i) = 36 - 9i^2 = 36 - 9[-1] = 36 + 9 = 45$

Extended Information on the Complex Number System

$\displaystyle \sqrt{-1} = i \\ -1 = i^2 \\ -i = i^3 \\ 1 = 4\:[Any\:multiple\:of\:four]$

I am joyous to assist you anytime.