A linear function has the form
[tex]y=mx+b[/tex]
so number 2 is a linear function. The graph of the linear is
and it models constant growth.
A quadratic function has the form
[tex]y=ax^2+bx+c[/tex]
so number 1 is quadratic. The graph of the quadratic is
and is decreasing in
[tex](-\infty,-4)[/tex]
An exponential function has the form
[tex]y=a^x,\text{ a>0}[/tex]
then the number 3 is exponential. The graph of the exponential is
and eventually excedees the other functions.
