# Math Help - polynomials and synthetic division

1. ## polynomials and synthetic division

Hi;
I know how to do synthetic division but I need to clear something up.

If the poly is being divided by say (x-4) should I use +4 in synthetic division
and if that divisor was (x+4) should I use -4 because swapping the signs makes things add up.

and is this always the case ie just swap signs and things work out?

Thanks.

2. ## Re: polynomials and synthetic division

Yes.

If $x=a$ then $(x - a)$ is a factor of the polynomial. Conversely, if $x= (-a)$ then $(x + a)$ is a factor of the polynomial.