c) $\frac{1}{x y - x^{2}} - \frac{1}{y^{2} - x y}$ ;

Question

c) $\frac{1}{x y - x^{2}} - \frac{1}{y^{2} - x y} = \frac{1}{x (y - x)} - \frac{1}{y (y - x)}$

$= \frac{y}{x y (y - x)} - \frac{x}{x y (y - x)} = \frac{y - x}{x y (y - x)} = \frac{1}{x y}$ ;

Answer 1

Trả lời:

Giải bởi Vietjack

c) $\frac{1}{x y - x^{2}} - \frac{1}{y^{2} - x y} = \frac{1}{x (y - x)} - \frac{1}{y (y - x)}$

$= \frac{y}{x y (y - x)} - \frac{x}{x y (y - x)} = \frac{y - x}{x y (y - x)} = \frac{1}{x y}$ ;

c) 1xy−x2−1y2−xy;