Can someone please help with this calculus problem?

Question

Find the critical numbers of the function:

f(x) = x^3 + x^2 +x


(I tried it but if the quad formula gives a nonreal number, how can we find the critical numbers?)

Answer 1

it has no critical points, which simply means that it is always increasing throughout the whole function.

Answer 2

That just means it doesn't have any.
I checked a plot of the graph myself to make sure.
Well, it doesn't have any maximum or minimum values,
which is what critical values are I think.
Maybe someone will have a better answer for you.

Answer 3

Give us your definition of "critical numbers."