Answer: answer is 66, this is how i got it.
If a=4 B=2 C=7
Equation: 3ac
First, 3(A=4) 3(4) for the first one you already said a=4 so you have to put the 4 in the A's spot
Second, 3(4)(C=7) 3(4)(7) for the letter C you know C is equal to 7, so replace the C with 7,
Third, Now you have to multiple 3x4=12 and multiply 3x7= 21
fourth, Add those two together 33, and multiply by B(2)
Step-by-step explanation: i really hope this is correct i'm sorry if its not but i tried and goodluck!