Factor using the GCF. If the expression cannot be factored, enter the expression as is.

Answer:
9m²n⁴
Step-by-step explanation:
9m²n⁴ = 3² × m² × n⁴
72m⁸n⁴ = 2³ × 3² × m⁸ × n⁴
GCF = multiplication of all common factors amongst the 2 expression with the lowest power(yes it's the lowest power)
GCF = 3²m²n⁴ = 9m²n⁴