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