Answer:
HCF = x
Explanation:
Comment
I'd be surprised is there was any other factor but 1. Oops. See below. There is a common factor other than 1. Whatever the value of x is is a common factor!
Formula
(x + 1)x(x + 8)
Solution
(x + 1)(x + 8)*x Multiply the first 2 factors
(x^2 + x + 8x + 8)*x Combine
(x^2 + 9x + 8)*x Remove the brackets
x^3 + 9x^2 + 8x Take out the common factor -- x
x(x^2 + 9x + 8)
Answer
Whatever the highest common factor is x which could be just about anything.