The other factor is 1.
Factor 2x plus 12x plus 28 is (x - 3)(x - 9)
(a + 2b)(a + 2b)
a + b + 4 is in its simplest form.
factor the trinomial 16x^2+24x+9
You can't factor it
That does not factor neatly.
Since the problem has 4 terms, first you factor x cubed plus 9x squared, then you factor 2x plus 18. So when you factor the first two term, you would get x sqaured (x plus 9). Then when you factor the last two terms and you get 2 (x plus 9). Ypure final answer would be (x squared plus 2)(x plus 9)