Question

Which of the following is the conjugate of a complex number with −4 as the real part and 2 as the imaginary part?

2i − 4

2i + 4

−4 − 2i

−4 + 2i

Answer 1

Complex numbers always take the form

a+bi

and the conjugate of that would be

a - bi

So what might the answer be?

Answer 2

would it be -4+2i

Answer 3

@AllTehMaffs

Answer 4

almost. That's the original expression. The conjugate of that, where the imaginary term is negated, is what we want.

Our original expression is

-4 + 2i

so negating the second part gives

-4 - 2i