Answer:GCF = 6
Step-by-step explanation=Notice we have these factorizations
12 = 6*2
18 = 6*3
Which shows that 6 is the greatest common factor (GCF)
So,
12+18 = 6*2+6*3 = 6*(2+3)
We use the distributive property which is a(b+c) = ab + ac
I'll leave the 2+3 part un-simplified so that you can see the two original pieces, and how the 6 can multiply with them both to get back to 12+18 again.
original sum rewrites to 6(2+3)
