Допоможіть будь ласка! Спростіть вираз:х - 3 - 3 - y xy- x^2 xy - y^2

Решите задачу:

$\frac{x-3}{xy- x^{2} } - \frac{3-y}{xy-y^2}= \frac{x-3}{xy- x^{2} } + \frac{3-y}{-(xy-y^2)}= \frac{x-3}{xy- x^{2} } + \frac{3-y}{y^2-xy}=\\ = \frac{x-3}{x(y- x)} } + \frac{3-y}{y(y-x)}=\frac{y(x-3)+x(3-y)}{xy(y- x)} }=\frac{xy-3y+3x-xy}{xy(y- x)} }=\frac{-3y+3x}{xy(y- x)} }= \\ \frac{-3(y-x)}{xy(y- x)} }= \frac{-3}{xy} =- \frac{3}{xy}$