Chapter 10 - Section 10.6 - Factoring General Trinomials - Exercise - Page 356: 10

$3(2x-1)(x+1)$

For the polynomial $$ 6x^2 +3x - 3=3(2x^2 +x - 1) $$ we check the factors of $ac=-1(2)=-2$. The only factors that can give the right middle term are $-1$ and $2$, as follows $$ 6x^2 +3x - 3=3(2x^2 +x - 1)=3(2x-1)(x+1) $$