Answer:
The answer to your question is: x - 4 is not a factor
Explanation:
x - 4 is a factor of 4x³ - 20x² + 18x -12
We can do synthetic division to know if it is a factor
4 - 20 +18 -12 4
16 -16 8
4 -4 +2 -4
x -4 is not a factor because there was a residue of -4