A) (11 -x)/(x +1) =x -4
11 -x =(x -4)(x +1)
11 -x =x² -3x -4
11 -x -x² +3x +4 =0
-x² +2x +15 =0 *(-1)
x² -2x -15 =0
D=4 +60 =64 =8²
x1=(2 -8)/2 = -3
x2 =(2 +8)/2 =5
b) x² -4 =(x +2)(x -2)
x² -2x =x(x -2)
1/x(x-2) -8/x(x+2)(x-2) +1/(x+2) =0
(x +2 -8 +x(x -2)) /x(x² -4) =0
x -6 +x² -2x =0
x² -x -6 =0
D=b² -4ac(a=1,b= -1,c= -6)
D=1 +24 =25 =5²
x1,x2=(-b+-корень изD)/2a
x1 =(1 -5)/2 = -2
x2 =(1 +5)/2 =3
ответ: x= -2, x =3