Question 966023
Be sure you include all "place values" which the dividend represents, even if they are 0.



x+3_____________|__________________________________________________________
_______________|______x^4________0*x^3_______0*x^2________0*x________81
_______________|
_______________|____________________________



x+3_____________|______x^3____________________________________________________
_______________|______x^4________0*x^3_______0*x^2________0*x________81
_______________|______x^4________3x^3
_______________|____________________________



x+3_____________|______x^3____________________________________________________
_______________|______x^4________0*x^3_______0*x^2________0*x________81
_______________|______x^4________3x^3
_______________|____________________________
_______________________0________-3x^3_______<i>0*x^2</i>



x+3_____________|______x^3_______-3x^2_____________________________________________
_______________|______x^4________0*x^3_______0*x^2________0*x________81
_______________|______x^4________3x^3
_______________|____________________________
_______________________0________-3x^3_______<i>0*x^2</i>
________________________________-3x^3_______-9x^2
_____________________________________________________
__________________________________0__________9x^2



You should continue and finish this....
Tell if you have trouble.  The process works just like you have already been taught as for Long Division.