Question

(-3 - 5i )(-3 + 5i ) = -16 34 34 - 30

Answer 1

You can use:

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

We know:

$i=\sqrt{-1}\to i^2=-1$

Calculate:

$(-3-5i)(-3+5i)=(-3)^2-(5i)^2=9-25i^2=9-25(-1)=9+25=34$