What is the product and conjugate of 3+9i?

Question

i dont remember what a conjugate is!!!!

Answer 1

Note that:

The complex conjugate of a complex number is given by changing the sign of the imaginary part. Thus, the conjugate of the complex number

3+9i is

3- 9i

If the product of the conjugates is what you are looking for:

(3+9i)(3-9i) = 3^2 - (9i)^2 =9+81 = 90  

Answer 2

The product of what?  Products usually require two expressions to multiply.

The conjugate of 3 + 9i, however, is 3 - 9i.