Let's first expand the expression:

(х + 2)(х^2 + х + 1)(х - 1)
= (х^3 + х^2 + х + 2х^2 + 2x + 2)(х - 1)
= (х^3 + 3х^2 + 3x + 2)(х - 1)
= х^4 + 3х^3 + 3х^2 + 2х - х^3 - 3х^2 - 3x - 2
= х^4 + 2х^3 - x - 2

Now, we have the expression as х^4 + 2х^3 - x - 2.

Since this expression equals 28 according to the given equation, we can set it equal to 28 and solve for x:

х^4 + 2х^3 - x - 2 = 28
х^4 + 2х^3 - x - 30 = 0

I'll leave it to you to solve this equation and find the values of x.