solve by factoring (i know they are are divisible by 14, but I'm stuck) Thank you
210x^3 + 266x^2 + 14x - 42 = 0
210x^3 + 266x^2 + 14x - 42
=14(15x^3 + 19x^2 + x - 3)
A little synthetic division and application of the Rational Roots Theorem yields
=14(x+1)(15x^2 + 4x - 3)
That will take some fiddling, but since the discriminant is a perfect square (196), you know that it can be done. Maybe just run it through the quadratic formula, and you have
=14(x+1)(5x+3)(3x-1)