Answer
$$(x-4)(3x+2) $$
Work Step by Step
First, for the polynomial $3x^2 - 10x - 8$, we write $$ 3x^2 - 10x - 8=3x^2 -12x +2x-8 .$$ By grouping the first two terms and the second two terms and then taking common factors, we have
$$3x^2 -12x +2x-8 =3x(x-4)+2(x-4)=(x-4)(3x+2) .$$