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 +3 = (x - (-3))`:

`-3`	`1`	`1`	`-13`	`-2`
		`-3`	`6`	`21`
	`1`	`-2`	`-7`	`19`

The last entry of the row is the remainder, `19`.

So the value of `x^3+x^2-13 x-2` when `x = -3` is `19`.