4-3<9
5-3<9
6-3<9
and so on...
Hello.
is a quadratic function, because it has an (x squared, or x times x) term.
Here's what linear functions look like:
A graph of a linear function is a line.
Quadratic functions look like so:
A graph of a quadratic function is a parabola.
Therefore, the given function is a quadratic function.
I hope this helps.
Have a nice day.