Answer:
5
Step-by-step explanation:
If a complex number is defined as a+bi, then its conjugate is defined as
[tex]\overline{z}=a-bi[/tex]
and the product of the complex number and its conjugate is
[tex]z\overline{z}=(a+bi)(a-bi)=a^2+b^2[/tex]
The given complex number is
[tex]z=1+2i[/tex]
The conjugate of given number is
[tex]\overline{z}=1-2i[/tex]
The product of the complex number and its conjugate is
[tex](1+2i)(1-2i)=1^2+2^2=1+4=5[/tex]
Therefore, the product of the complex number and its conjugate is 5.
