You can use:
[tex](a-b)(a+b)=a^2-b^2[/tex]
We know:
[tex]i=\sqrt{-1}\to i^2=-1[/tex]
Calculate:
[tex](-3-5i)(-3+5i)=(-3)^2-(5i)^2=9-25i^2=9-25(-1)=9+25=34[/tex]
Answer:
(-3 - 5i )(-3 + 5i ) = 34 , I'm pretty sure 34 is the answer.
