x^3+2x^2+x+12 divided by x+3

i cannot figure this out can anyone help?

It goes like this, just like long division. In this case, becasue of the zero at the bottom, there is no remainder (but there usually is). I will have to use dots to keep the spacing right

x^2 - x + 4
.....______________________
x+3 | x^3 + 2x^2 + x + 12
.......x^3 + 3x^2
-----------------
.............-x^2 + x
.............-x^2 -3x
----------------------
.................. 4x + 12
...................4x + 12
---------------------------
.......................0