Split the second term in 6x^2 + 17x + 5 into two terms
6x^2 + 15x + 2x + 5 = 0
Factor out common terms in the first two terms, then in the last two terms.
3x(2x + 5) + (2x + 5) = 0
Factor out the common term 2x + 5
(2x + 5)(3x + 1) = 0
Solve for x
x = -5/2, -1/3