Answer: (x^2 + 7)(x-4)
Explanation:
1. Group the first two terms and the second two terms
2. Factor the first two terms by taking out the GCF
x^2(x-4)
3. Factor the second two terms by taking out the GCF
7(x-4)
4. Combine!
(x^2 + 7)(x-4)
5. Check your work
x^3 - 4x^2 + 7x -28