determine all intervals on which $f(x)leq0$.

Explanation:

Step1: Identify x - values where f(x) is below or on x - axis

We look at the graph of (y = f(x)). The function (y=f(x)) is less than or equal to 0 when the graph is on or below the x - axis.

Step2: Determine the intervals

From the graph, we can see that the function (f(x)\leq0) on the intervals ([-8,-6]\cup[-3,1]\cup[7,9]).

Answer:

([-8,-6]\cup[-3,1]\cup[7,9])