Patrick B. answered 11/20/20
Math and computer tutor/teacher
P = +or- {1,2,4,8}
Q = +or- {1}
so p/Q = P = +or- {1,2,4,8}
f(-1) = (-1) + (-1) -2 +12-8 = 0,
so x=-1 is a solution and (x+1) is a factor
-1 | 1 0 1 -2 -12 -8
-1 1 -2 4 8
___________________________
1 -1 2 -4 -8 0
the quotient is x^4 - x^3 + 2x^2 - 4x - 8 = Q(x)
Q(-1) = 1 - -1 + 2 + 4 - 8 = 0,
so again, x=-1 is a solution and (x+1) is a factor
-1 | 1 -1 2 -4 -8
-1 2 -4 8
_________________________
1 -2 4 -8 0
x^3 - 2x^2 + 4x-8 = 0
x^2(x-2) + 4(x-2) = 0
(x^2+4)(x-2) = 0
x-2 = 0 or x^2 + 4 = 0
x=2 or x = +or-2i
check: f(2) = 32 + 8 - 8- 24 - 8 = 0
f(2i) = (2i)^5 + (2i)^3 - 2(2i)^2 - 12(2i) - 8 =
32i -8i +8 - 24i - 9 = 0
So x=2 and x=2i are solutions, which forces x=-2i
must also be a solution
the solution set is x = {-1,-1,2, 2i, -2i}