The GCF stands for "greatest common factor", it means the greatest monomial or number that is a factor of all the elements in the expressions. To factor the expressions we must find this number or monomial and divide all the numbers by it, representing the expression as a product of the GCF with the divided expression. This is done below:
1)
If we look at all the factors the only common factor between them is "3", therefore:
2)
If we look at all the factors the only common factor between them is "6", therefore: