McDougal Littell Algebra 2, Chapter 5, 5.2, Section 5.2, Problem 43

We can solve this using the AC factoring method:
18n^2 + 9n - 14
Multiply a by c
18 x -14 = -252
Find factors of -252 that add up to b (9)
1 x 252, 2 x 126, 3 x 84, 4 x 63, 6 x 42, 7 x 36, 9 x 28, 12 x 21, and 14 x 18
As you can see only -12 and 21 meet the requirement, plug these in as b
18n^2 + 21n -12n - 14

now group:
(18n^2 + 21n)( -12n - 14)

Factor out the greatest common factors:
3n (6n + 7 ) - 2 (6n + 7)
Put the numbers outside in a parentheses together :
(3n - 2) (6n + 7)