Answer: 1 and 3
Step-by-step explanation: For the fractions 3/4 and 7/12, let's list the factors of each numerator and denominator:
Factors of 3: 1, 3
Factors of 4: 1, 2, 4
Factors of 7: 1, 7
Factors of 12: 1, 2, 3, 4, 6, 12
From the lists above, we can see that the common factors of 3/4 and 7/12 are 1 and 3.