The graph of $y=x^3-4x$ is shown in the figure. How many zeroes does the polynomial $x^3-4x$ have? 

The zeroes are the $x$-coordinates where the graph intersects the $x$-axis. In the figure, the curve meets the $x$-axis at three points: $x=-2$, $x=0$, and $x=2$. So the polynomial has 3 zeroes.