What does "f(0), f(3) = 0, f''(1) 0" mean?

Since f'(x) < 0 for x < -2 and -2 < x < 0, the function is monotonic on those intervals and therefore has limits from the left and from the right at -2. Since there is no overall limit, the one-sided limits must be different.

Also, you need to make sure the function is concave/convex on the required intervals.