We know that a function is greater than 0 when the graph of the function is above the x-axis.
Meaning that if the function is below the x-axis the function is taking negative values.
For that reason we can say that:
A) f(-2) is positive because the graph at that point is above the x-axis
B) the function is greater than 0 o values greater than -3 until 5, in interval notation it will be (-3,5]
c) We can say that the function is equal to 0 when x=-3 because at that point the graph is exactly crossing the x-axis