To factor the expression \( 12y + 6 \) using the greatest common factor (GCF), we first determine the GCF of the coefficients 12 and 6.
The GCF of 12 and 6 is 6.
Now, we can factor out the GCF from the expression:
\[ 12y + 6 = 6(2y + 1) \]
Thus, the factored form of \( 12y + 6 \) is:
\[ 6(2y + 1) \]