Simplify x−2−y−2x−1−y−1\frac{x^{-2} - y^{-2}}{x^{-1} - y^{-1}}x−1−y−1x−2−y−2.
x+yxy\frac{x+y}{xy}xyx+y
x−yxy\frac{x-y}{xy}xyx−y
y+xx−y\frac{y+x}{x-y}x−yy+x
1x+1y\frac{1}{x} + \frac{1}{y}x1+y1