The answer is 35(3+m).
To find the GCF, we find the prime factorization of both numbers:
105 = 5*21 = 5*3*7 = 3*5*7
35 = 5*7
Both numbers have the factors 5 and 7, so 5*7=35 is the GCF. This is what we bring out of the parentheses:
35( )
Dividing 105 by 35, we have 5 left over:
35(5+ )
Taking 35 out of 35m, we have m left over:
35(5+m)
