## Calculus (3rd Edition)

$$x=0, x=\pm 2.$$
The zeros of $f(x)= x^3-4x$ can be obtained by putting $$x^3-4x=0\Longrightarrow x(x^2-4)=0 \Longrightarrow x=0, x=\pm 2.$$ Since $f(-x)=-f(x)$.