Answer
$1$ positive real zero, $2$ imaginary zeros
Work Step by Step
We are given the function:
$$f(x)=x^3+2x-11.$$
First we count the number of sign changes:
$$+,+,-.$$
The coefficients of $f(x)$ have one sign change, so $f$ has $1$ positive real zero.
We determine $f(-x)$:
$$f(-x)=(-x)^3+2(-x)-11=-x^3-2x-11.$$
We count the number of sign changes:
$$-,-,-.$$
The coefficients of $f(-x)$ have no change of sign, therefore there is no negative real zero.
To summarize, we got that the function has one positive real zero and two imaginary zeros.