I don't understand how the LHS equals the RHS for this:

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

Then this statement follows which i also don't understand.

"Turning points when dy/dx = 0 are when x^2 - 1 = 0, that is when x = -1, 1.

Note that dy/dx is undefined at x = 0."

Any help would be much appreciated.