Question 1094566
You need to apply the change-of-base formula. For your calculations, you can use ln or  log_10 as long as you use the same base for both numerator and denominator. I used ln, but either will give you the same result:
log_b(x) = (log_d(x))/(log_d(b)
log_3(12) = (ln(12))/(ln(3)) = 2.261
log_3(28) = (ln(28))/(ln(3)) = 3.033
log_3(63) = (ln(63))/(ln(3)) = 3.771
2.261-3.033+3.771 = 2.999 (the answer is probably 3 because of decimal rounding)