Find the product of the given complex number and its conjugate.
1/5+4i

-15.96

Step-by-step explanation:

A conjugate is a binomial with the sign inside changed. So the conjugate of (1/5 + 4i) is (1/5 - 4i)

Set the original and the conjugate next to each other and F.O.I.L. Multiply the first numbers of each binomial, the 1/5 and the 1/5 to get 1/25. This is the "F."

Multiply the outer members, the 1/5 and the 4i to get - 60i. This is the "O."

Multiply the inner  numbers  ( the + 4i and the 1/5) to get + 60i. This is the "I."

Multiply the positive 4i and the negative 4i to get 16i squared

The positive 60i and the negative 60i cancel each other out.

The i squared changes into - 1. This makes the 16 negative.

Add 1/25 to - 16 to get - 15.96

fist on the left goes with the third on the right. second on the left goes with the fourth on the right. third on the left goes with the second on the right. the fourth on the left goes with first on the right