Answer:

A

Step-by-step explanation:

X^2 - 1 / x-1 = (x+1)(x-1)/x-1 = x+1

Through simplifying the numerator through factoring, we can now cancel x-1 from the numerator and x-1 from the denominator because if we will divide them, it is equal to zero. So the remaining x+1 multiplied by 1 is equals to x+1.