To factor \( 18m - 24n \) using the greatest common factor (GCF), we first need to find the GCF of the coefficients 18 and 24.
The factors of 18 are: 1, 2, 3, 6, 9, 18
The factors of 24 are: 1, 2, 3, 4, 6, 8, 12, 24
The greatest common factor is 6.
Now, we factor out 6 from the expression:
\[ 18m - 24n = 6(3m - 4n) \]
Thus, the correct answer is:
6(3m − 4n)