Question 251051
Don't be confused. Break it down into things you already know.
{{{(x-3)^3}}} something cubed means multiplied by itself 3 times. So
{{{(x-3)(x-3)(x-3)}}} Now multiply the first two terms
{{{(x^2-3x -3x +9)(x-3)}}} collect terms
{{{(x^2-6x +9) (x-3)}}} now multiply again
{{{x^3-3x^2 -6x^2 + 18x +9x -27}}}  again. collect terms
{{{x^3 -9x^2 + 27x -27}}}

http://www.wolframalpha.com/input/?i=%28x-3%29^3