Simplify: 1x−1y1x+1y\frac{\frac{1}{x} - \frac{1}{y}}{\frac{1}{x} + \frac{1}{y}}x1+y1x1−y1 (assume x,y≠0x, y \neq 0x,y=0, x≠−yx \neq -yx=−y).
y−xy+x\frac{y-x}{y+x}y+xy−x
x−yx+y\frac{x-y}{x+y}x+yx−y
y+xy−x\frac{y+x}{y-x}y−xy+x
xyxyxy