Answer:
(5 + 3i)(5 − 3i) = 34
Step-by-step explanation:
The multiplication of two identical binomials who have different symbol, can be solved using the factoring case of a difference of squares:
[tex](a-b).(a+b)=a^{2}-b^{2}[/tex]
So, in this case:
[tex](5+3i).(5-3i) = 5^{2}-(3i)^{2}[/tex]
[tex]=25-9i^{2}[/tex]
Remember that [tex]i=\sqrt{-1}[/tex]
So: [tex]i^{2}=-1[/tex]
We replace on the polynomial:
[tex]=25-9.(-1) = 25+9=34[/tex]
