Completely factor the polynomial. 12x^2 + 2x - 4

2 ( 3 x + 2 ) ( 2 x − 1 )

I would reccomend using the rainbow method for this since there is a number infront of x^2 

1. Find your magic number   Multiply 12 * -4  = -48 
2. You want a number that multiplies to -48 but adds to 2 
12   -4    + 8
8     -6     +2   This is it. 
3. Substitute those numbers for your middle number 
12x^2 -6x + 8x -4   
4. Factor by grouping
(12x^2 -6x) + (8x-4) 
5. Pull out GCF 
6x(2x-1)  +  4(2x-1) 
(6x+4)(2x-1)