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

##### 1 Answer

Jul 26, 2016

#### Explanation:

Note that for any

#a^2-b^2 = (a-b)(a+b)#

So we find:

#(7-3i)(7+3i) = 7^2-(3i)^2 = 49-9i^2 = 49+9 = 58#

Jul 26, 2016

Note that for any

#a^2-b^2 = (a-b)(a+b)#

So we find:

#(7-3i)(7+3i) = 7^2-(3i)^2 = 49-9i^2 = 49+9 = 58#

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