Answer:
39
Step-by-step explanation:
4 x 1 x 3 + 3 x 1 x 2 + 7 x 3
4 x 3 + 3 x 1 x 2 + 7 x 3
12 + 3 x 1 x 2 + 7 x 3
12 + 3 x 2 + 7 x 3
12 + 6 + 7 x 3
12 + 6 + 21