Why does multiplying a + bi by the complex conjugate a -bi eliminate i from the expression

EXPLANATION

The reason is that

If we multiply by its conjugate

We obtain;

This is difference of two squares so we obtain;

This further gives us,

Since the , we substite to get;

The is now eliminated and we get,

we'll this would mean that the dunk tank and the bounce house are the same for 20 hours because the 2 represents that the two activities, and the 20 represents the amount of hours they both are. so with this said, it means that the answer is c. the costs for a dunk tank and bounce house are the same for 20 hours.

c.the costs for a dunk tank and bounce house are the same for 20 hours.

hope this .