hey everbody got an assignment from my math teacher today that me and the rest of the class are absolutly stumped on"

f(x) = X^4 - 3x^3 - 13x^2 + 3X + 12

f(-1) = 0

Then i synthetically divided and came up with this unfinished division statement.

Therefore: X^4 - 3x^3 - 13x^2 + 3X + 12

= ( X + 1 ) ( X^3 - 4X^2 - 9X + 12)

= ryguy272 totally stuck

ANY HELP APPRECITATED ( i cant spell )