#### Answer

In order to simplify a rational expression to its lowest terms you have to find the lowest common factor of that the numerator and denominator share. You then factorise out this multiple.
$\frac{3x^{2}-3x}{3x^{3}-6x^{2}+3x}$ = $\frac{3x(x-1)}{3x(x^{2}-2x+1)}$
Once you've factorised out the lowest common multiple, you can simply cancel them and you have the lowest form of the rational expression.
$\frac{3x(x-1)}{3x(x^{2}-2x+1)}$ = $\frac{x-1}{x^{2}-2x+1}$

#### Work Step by Step

Answer is explaination