Answer :
find the common factor and then choose the greatest (biggest one)
45= 3,5,9,15,45
81= 3,9,27,81
The common factors are 3 and 9
The greatest common factor (GFC) is 9
45= 3,5,9,15,45
81= 3,9,27,81
The common factors are 3 and 9
The greatest common factor (GFC) is 9
Answer: 9
Step-by-step explanation: what is the greatest number that they can be multiplied by
9*9=81
9*5=45