Final answer:
The GCF of the monomials 3s³ and 3s² is 3s², as the coefficient 3 is common in both and s² is the lowest power of the variable present in both terms.
Step-by-step explanation:
The Greatest Common Factor (GCF) of monomials is found by identifying the common factors in both the coefficient parts and the variable parts raised to their powers. The GCF is the product of these common factors. In the case of the monomials 3s³ and 3s², the GCF is straightforward as the coefficients (3 and 3) are the same, and we take the lowest power of the variable present in both (which is s²). Thus, the GCF is 3s².