Interception with $x$-axis - not so trivial? I want to find the interception with the x-axis of the following function:
$f(x) = \frac{1}{4}x^4-x^3+2x$.
So putting $0 = \frac{1}{4}x^4-x^3+2x$ I would get $0 = x(\frac{1}{4}x^3-x^2+2)$ but how to check for the other solutions properly?

Also $x=2$ is a root, so $f(x)=\frac{1}{4}(x-2)x(x^2-2x-4)$.  wolframalpha is your friend.
