Move all terms to one sides
3x^2 - 14x - 5 = 0
Split the second term in 3x^2 - 14x - 5 into two terms
3x^2 + x - 15x - 5 = 0
Factor out the common terms in the first two terms, then in the last two terms;
x(3x + 1) - 5(3x + 1) = 0
Factor out the common term 3x + 1
(3x + 1)(x - 5) = 0
Solve for x;
x = -1/3, 5