The remainder theorem tells us the value of a polynomial when `x = a` is the remainder when the polynomial is divided by `x - a`.

We'll use synthetic division to divide by `(x - 5)`:

`5`	`1`	`-16`	`72`	`-96`
		`5`	`-55`	`85`
	`1`	`-11`	`17`	`-11`

The last entry of the row is the remainder, `-11`.

So the value of `x^3-16 x^2+72 x-96` when `x = 5` is `-11`.