Find the product of -4-2i and it’s conjugate the answer is a+bi where

Question

Help I have been stuck on this I need help

Answer 1

(-4-2i)(-4+2i)=16-(2i)²=16+4=20 or in a+bi form that's 20+(0)i, but usually if b=0 you just omit the bi term

there is only a real component, no imaginary term The imaginary terms cancel

when you multiply conjugates

multiplying by a conjugate eliminates the OI in the FOIL method.

For example, (a-b)(a+b)=a²-b² eliminating the ab terms since they cancel each other.

(a-b)(a+b)=a²+ab-ab-b²

The conjugate of a-bi is a+bi. Just change the sign of the imaginary term