Question

Помогите плезз
$frac{x+4}{xy-x^{2}} + frac{y+4}{xy- y^{2} }$

Answer 1

$frac{x+4}{x(y-x)} - frac{y+4}{y(y-x)}= frac{xy+4y-xy-4x}{xy(y-x)} = frac{4(y-x)}{xy(y-x)}= frac{4}{xy}$

Answer 2

ты x пропустил(

Answer 3

торопился :)

Answer 4

$displaystyle frac{x+4}{xy-x^2} + frac{y+4}{xy-y^2}= frac{x+4}{x(y-x)}+ frac{y+4}{y(x-y)} =\ \ \ = frac{-y(x+4)+x(y+4)}{xy(x-y)} = frac{-xy-4y+xy+4x}{xy(x-y)} =\ \ \ = frac{4x-4y}{xy(x-y)}= frac{4(x-y)}{xy(x-y)}= frac{4}{xy}$