Question 889189
Try looking for possible rational roots and check them until you have all of degree three taken care of.


1,2,5,10,20,25,50.  Use synthetic division to check each of those as possible roots.  Review Rational Roots Theorem.


One root is seen on a graph, but it is probably NOT rational; most likely must be irrational.  None of the "possible" roots I listed is any rational root for x^3+100.  Best guess, the value looks like cubed root of 100.