Simplify: xy−yx1+yx\frac{\frac{x}{y} - \frac{y}{x}}{1 + \frac{y}{x}}1+xyyx−xy
x−yy\frac{x-y}{y}yx−y
x+yx\frac{x+y}{x}xx+y
x2−y2xy+y2\frac{x^2-y^2}{xy+y^2}xy+y2x2−y2
x−yx\frac{x-y}{x}xx−y