Step-by-step explanation:
Write the prime factorization of each term:
9r⁵s = 3² × r⁵ × s
6r⁴s² = 2 × 3 × r⁴ × s²
12r²s = 2² × 3 × r² × s
The greatest common factor will have all the common factors raised to their lowest exponent.
So all three terms have 3, r, and s as factors. The lowest exponent of 3 is 1. The lowest exponent of r is 2. The lowest exponent of s is 1.
GCF = 3 × r² × s
GCF = 3r²s
Factor out the GCF:
9r⁵s + 6r⁴s² − 12r²s
3r²s (3r³ + 2r²s − 4)