polynomial division and remainder theorem

Hi;

use remainder theorem to find the remainder of (3x^4 - 5x^2 - 20x -8) / (x + 1).

When using remainder theorem I get remainder -33

and with long division I get remainder 10 which I think is the right answer.

Not sure why I'm getting -33 with remainder theorem

What am I missing?

Thanks.

Re: polynomial division and remainder theorem

The correct answer *is* 10. Post your working.

Re: polynomial division and remainder theorem

...

Code:

`-1] ... 3 ... 0 ... -5 ... -20 ... -8`

.............-3 ....3.......2 ... 18

---------------------------------------

.......3.....-3....-2.....-18 ... 10

Re: polynomial division and remainder theorem

Quote:

Originally Posted by

**anthonye** Hi;

use remainder theorem to find the remainder of (3x^4 - 5x^2 - 20x -8) / (x + 1).

When using remainder theorem I get remainder -33

and with long division I get remainder 10 which I think is the right answer.

Not sure why I'm getting -33 with remainder theorem

What am I missing?

Thanks.

Using the remainder theorem,

$\displaystyle f(-1)$

$\displaystyle = 3(-1)^4 - 5(-1)^2 - 20(-1) - 8$

$\displaystyle = 3 - 5 + 20 - 8$

$\displaystyle = 10$

Re: polynomial division and remainder theorem