Answer
$3x^{3}-x^{2}-12x+4=(3x-1)(x-2)(x+2)$
Work Step by Step
$3x^{3}-x^{2}-12x+4$
Group the first and third terms together. Do the same with the second and fourth terms:
$3x^{3}-x^{2}-12x+4=(3x^{3}-12x)+(-x^{2}+4)=...$
Take out common factor $-1$ from the second parentheses:
$...=(3x^{3}-12x)-(x^{2}-4)=...$
Take out common factor $3x$ from the first parentheses:
$...=3x(x^{2}-4)-(x^{2}-4)=...$
Take out common factor $(x^{2}-4)$:
$...=(3x-1)(x^{2}-4)=...$
Finally, factor the difference of squares in the second parentheses:
$...=(3x-1)(x-2)(x+2)$
