#### Answer

Concave upward on
$$
(-\infty, 3).
$$
Concave downward on
$$
(3, \infty).
$$
Inflection point at
$$
(3,7).
$$

#### Work Step by Step

Since the graph of the function lies above its tangent line at each point of $(-\infty, 3)$.
So, concave upward on
$$
(-\infty, 3).
$$
Since the graph of the function lies below its tangent line at each point of $(3, \infty)$ .
So, concave downward on
$$
(3, \infty).
$$
Since a point where a graph changes concavity is $(3,7).$
So, Inflection point at
$$
(3,7).
$$