I have worked on this problem for several days and gotten nowhere, but maybe this will help since you have gotten no answers yet.
if you make the substitution suggested: x2t = x3+x2+x
dt= [(x2-1)/x]dx and the integral becomes ∫ [x/(x+1)] dt/√t which, as far as I can tell is no help...but maybe you will see something that I do not.
Lastly note that the expression under the radical = x(x3 - 1)/(x-1).
None of this has helped me complete the integral...but maybe you can get it with this help.
I apologize that I am not more helpful.
Also if/when you get the answer. I would be grateful if you would share it with me...I am always interested to learn something new! Thanks.