From the graph given in the question, we are asked to determine the following observing the graph:
(a) The domain of f.
Domain of f = IR = (-infinity, infinity)
(Therefore, it is defined all reals).
(b) The range of f.
The range of f = [-1, infinity)
(c) The x-intercepts.
x = 2 and x = 4 are the x intercepts.
(d) The y-intercepts.
y = 8 is the only y-intercept.
(e) Intervals on which f is increasing.
The function is increasing on (3, infinity)
(f) Intervals on which f is decreasing.
The function f is decreasing on (0, 3)