Hello!
The answer is:
The function is greater or equal to 0 at the points (-3,6), (-2,0), (0,6) and (4,0).
Why?
To find where the function is greater or equal to 0, we need to look (using the graph) where the function is above the x-axis
So, we can see that the function is above the x-axis from the point (-3,6) to the point (4,0), for these points, the function is greater or equal to 0.
Hence, the function is greater or equal to 0 at the points (-3,6), (-2,0), (0,6) and (4,0), or the function is greater or equal to 0, from -3 to 4 (x-axis values or input).
We have that:

Have a nice day!