Question

Question #3e8a6

Answer 1

`f(4)` could be any real number.

Explanation:

To see this graphically:

On a coordinate system, mark the points given points: `(2,7)`, `(3,9)`, and `(5,7)`.
Connect the first two with a line segment.

Now put in a point with `x`-coordinate `4` and any `y` coordinate you choose. I'll call it `d`. So you've marked a point `(4,d)`.
Now connect `(3,9)` and `(4,d)` with a line segment and connect `(4,d)` and `(5,7)` with a line segment.

Note. instead of line segments you could use any continuous curve(s) you choose to connect the 4 points.