okay so 15x^2+11x+2
step one: split the second term into two terms
15x^2 + 6x + 5x + 2
step two: factor out common terms in the first two terms, then in the last two terms
3x(5x+2) + (5x+2)
step three: factor out the common term 5x+2
(5x+2)(3x+1) (should be the answer)