X^2 -1 =(x -1)(x+1)
(6 -2(x+1)) /(x-1)(x+1) =(2(x+1)-(x-4))/(x+1)
(6 -2x -2)/(x-1)(x+1) =(2x+2 -x+4)/(x+1)
(4 -2x)/(x-1)(x+1) =(x-2)/(x+1)
(4 -2x -(x-2)(x-1)) /(x-1)(x+1) =0
4 -2x -(x^2 -3x +2) =0
4 -2x -x^2 +3x -2 =0
-x^2 +x +2 =0; *(-1)
x^2 -x -2 =0
D =1 +8 =9 =3^2
x1 =(1 -3)/2 = -1
x2 =(1+3)/2 =2
ответ: x= -1; x =2