Answer:
(4x -3)(√3x -1)(√3x +1)
Explanation:
Your factoring is correct for integers. However the quadratic term can be factored further using irrational coefficients. It is the difference of the squares of (√3)x and 1, so can be factored as such.
12x³ -9x² -4x +3 = 3x²(4x -3) -(4x -3) = (3x² -1)(4x -3)
= ((√3)x -1)((√3)x +1)(4x -3) . . . . . . further factoring the difference of squares