Rút gọn phân số:

To simplify the expressions, let's start with each one separately:

1) 2x - 1/x + a

2) (a - x) / (-x^2 + ax - a^2)

3) 2x^2 - 2 / x^3 + a^3

Now, let's simplify each expression:

1) 2x - 1/x + a

To simplify this expression, we need to find a common denominator for the terms involving x. The common denominator is x, so we can rewrite the expression as:

(2x^2 - 1 + ax) / x

2) (a - x) / (-x^2 + ax - a^2)

To simplify this expression, we can factor the denominator:

(-1)(x^2 - ax + a^2)

Now, we can rewrite the expression as:

(a - x) / (-1)(x - a)(x - a)

3) 2x^2 - 2 / x^3 + a^3

To simplify this expression, we can factor out a 2 from the numerator and a common factor of x from the denominator:

2(x^2 - 1) / x(x^2 + a^3)

Now, we have simplified the expressions.