Question

how do you subtract 2x+4/x^2 - 2/x^2-1

Answer 1

2x+4/x^2-1 - 2/x^2-1

Answer 2

Just take a common denominator. (Here, x^2-1)
So you can also write this as
(2x+4-2)/x^2-1
Or
2(x+1)/x^2-1
Then apply the identity on the denominator.
And ge the final answer as
2/(x-1)
Understood? :)