Simplify: 1−y2x21−yx\frac{1 - \frac{y^2}{x^2}}{1 - \frac{y}{x}}1−xy1−x2y2
x−yx\frac{x-y}{x}xx−y
x+yx\frac{x+y}{x}xx+y
xx+y\frac{x}{x+y}x+yx
1+yx1 + \frac{y}{x}1+xy