Question 297603
First step is to graph it.
{{{graph(300,300,-15,15,-100,100,x^3+2*x^2-88x+200)}}}
Yikes, unfortunately this equation does not have simple (integer or rational) 
roots. I suggest using www.1728.com/cubic.htm which has a cubic equation solver. From that site,
x=6.687,x=-11.327,x=2.640 are roots for this equation.