D. 6x(2x² - 6x + 1)
GCF - Greatest Common Factor
It is simply the largest of the common factors.
We have:
12x³- 18x² + 6x
We find GCF of 12, 18 and 6:
GCF(12, 18, 6) = 6
12 = 2 · 6
18 = 3 · 6
6 = 1 · 6
and GCF of x³, x² and x:
GCF(x³, x², x) = x
x³ = x² · x
x² = x · x
x = 1 · x
Therefore:
12x³- 18x² + 6x = 6x(2x² - 6x + 1)