Find the inflection points of f''(x)= x(x+1)(x-2)^2.
Explain
The inflection points of f(x) are where f"(x) = 0.
You don't say what f(x) is, but you don't have to.
Since you have already provided f"(x) , the inflection points of f(x) would be at x = 0, -1 and 2.