A particle P of mass 2 moves along x axis under F. F(x)=(9/x^2)-1

Show the time it takes for P to travel from x=1 to x=9 is $\displaystyle \int(1/(sqrt(10-x-9/x)) $ with limits 9 and 1.

I've found P(x) and V(x) by integrating F(x)/2 = a(x) twice but then I'm stuck