a) (\frac{x}{x+1}+1)\cdot \frac{1+x}{2x-1};

a)

$$(\frac{x}{x+1}+1)\cdot \frac{1+x}{2x-1} = (\frac{x+x+1}{x+1}) \cdot \frac{1+x}{2x-1} = \frac{(2x+1)(x+1)}{(x+1)(2x-1)} = \frac{2x+1}{2x-1}$$.

Ответ: $$\frac{2x+1}{2x-1}$$