5/(х-1) - 3/(х+1) = 15/(х²-1),
5*(х+1)/(х²-1) - 3*(х-1)/(х²-1) =15/(х²-1),
(5х+5)/(х²-1) - (3х-3)/(х²-1) = 15/(х²-1),
5х+5 - 3х+3 = 15,
2х = 15-5-3,
2х = 7,
х = 3,5 (или 3 1/2),
х - 1 ≠ 0, х + 1 ≠ 0,
х ≠ 1, х ≠ -1,
проверка корней:
5/(3,5-1) - 3/(3,5+1) = 15/(3,5²-1),
5/(2,5) - 3/(4,5) = 15/(11,25),
2 - 2/3 = 4/3,
1 3/3 - 2/3 = 1 1/3,
1 1/3 = 1 1/3