It's -1.
15 - 4 = 11
11 - 12 = -1
Answer:
not 100% sure
Step-by-step explanation:
40÷3=13.3 minutes
3BC
8BC - 9BC + 10BC - 6BC = BC(8 - 9 + 10 - 6) = BC(3) = 3BC
work is shown and pictured