\[ \frac{y^2 - 2y}{y^2} = \frac{y(y - 2)}{y \cdot y} = \frac{y - 2}{y} \]
\[ \frac{x^2 + 4x}{x^2 - 16} = \frac{x(x + 4)}{(x - 4)(x + 4)} = \frac{x}{x - 4} \]
Ответ: а) y-2/y; б) x/x-4