Answer
$f(x) = (-1/3)x^2$, $f(x) = -x^2$, $f(x) = 3x^2$
Work Step by Step
There are 2 ways to do this. The first way is by putting the equations into a graphing calculator, and then ranking them from widest to narrowest. The second way, if you don't have a graphing calculator, is that the closer the coefficient of $x^2$ is to 0, the wider it will be.
