The rate of change is simply the derivative of a function with respect to the other variable. In this case the rate of change with respect to x is desired. Therefore
f(x) = x^3 - 3x^2
f'(x) = 3x^2 - 6x
therefore the rate of change of y with respect to x is dy/dx = 3x^2 - 6x
Here is the graph, you can match it yourself:
When it was discovered, nobody knew how to read ancient Egyptian hieroglyphs. Because the inscriptions say the same thing in three different scripts, and scholars could still read Ancient Greek, the Rosetta Stone became a valuable key to deciphering the hieroglyphs!!