Integral of (-2)/(1-x^2)

I've been told I have to use integration by substitution. Any help would be really appreciated.

Thanks!

∫-2/(1 - x²) dx

∫2/(x² - 1) dx

∫[(x + 1) - (x - 1)]/(x + 1)(x - 1) dx

∫1/(x - 1) - 1/(x + 1) dx

= ln|(x - 1)/(x + 1)| + C

∫ - 2/(1 - x^2) dx
= ∫ 2/(x^2 - 1) dx
= ∫ [1/(x - 1) - 1/(x + 1)] dx
= ln lx - 1l - ln lx + 1l + c
= ln l(x - 1)/(x + 1)l + c.

-2 ArcTanh[x]