Упростим выражение.

a)

$$\frac{x^2}{(x - 5)^2} - \frac{25}{(5 - x)^2} = \frac{x^2}{(x - 5)^2} - \frac{25}{(x - 5)^2} = \frac{x^2 - 25}{(x - 5)^2} = \frac{(x - 5)(x + 5)}{(x - 5)^2} = \frac{x + 5}{x - 5}$$

б)

$$\frac{x^2 + 25}{(x - 5)^2} + \frac{10x}{(5 - x)^2} = \frac{x^2 + 25}{(x - 5)^2} + \frac{10x}{(x - 5)^2} = \frac{x^2 + 10x + 25}{(x - 5)^2} = \frac{(x + 5)^2}{(x - 5)^2}$$