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

1 Answer
Mia
Oct 18, 2016

#(2-3i)(2+3i)=13#

Explanation:

The given numerical expression is in the form of:
#color(blue)((a-b)(a+b)=a^2-b^2)#

Let us apply it
Here #a=2 and b=3i#

#(2-3i)(2+3i)#
#=2^2-(3i)^2#
#=4-9i^2#
As we know #i^2=-1#

Therefore,
#(2-3i)(2+3i)=4+9=13#

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