Questions: (left(x/(x+y)-(y/(2x-y))+(xy+y^2-y)/(2x^2+xy-y^2)right))

To simplify the given expression, we need to combine the fractions by finding a common denominator and then simplifying the resulting expression.

La expresión original es: $$\frac{x}{x+y} - \frac{y}{2x-y} + \frac{xy + y^2 - y}{2x^2 + xy - y^2}$$

Para simplificar la expresión, combinamos las fracciones encontrando un denominador común y simplificando el resultado. La expresión simplificada es: $$\frac{2x^2 - xy - y}{2x^2 + xy - y^2}$$

$$\boxed{\frac{2x^2 - xy - y}{2x^2 + xy - y^2}}$$