$\displaystyle \frac{x}{x-1}$\displaystyle \frac{x}{x-1}

$\displaystyle \frac{1}{3x^2-3x}$\displaystyle \frac{1}{3x^2-3x}

$-3x$-3x

$\displaystyle - \frac{1}{3x}$\displaystyle - \frac{1}{3x}