B) x²-2x+1 x-1 x²-25 x²+5x

4. $$ \frac{x^2-2x+1}{x^2-25} \times \frac{x-1}{x^2+5x} = \frac{(x-1)^2}{(x-5)(x+5)} \times \frac{x-1}{x(x+5)} = \frac{(x-1)^3}{x(x-5)(x+5)^2} $$

Ответ: $$ \frac{(x-1)^3}{x(x-5)(x+5)^2}$$