Question

x^3+9x^2+8x+72

Answer 1

factor four term polynomial by grouping

Answer 2

Group the first two terms and the second two terms: (x^3 +9x^2) + (8x +72)
Factor out the common factor from each grouping: x^2(x + 9) + 8 (x + 9)
Notice that both terms now have a common factor of (x + 9), so pull it out:
(x + 9) (x^2 +8)