Answer:
The first one
Step-by-step explanation:
1. 36/-3 = -12
2.-4-(-16) =12
3.(-3)(-4) = 12
4.21+ (-9) = 12
The first one is the only one which doesn't equal 12. It equals -12 and that's why it doesn't belong.
Let me know if you need further detail for them :)
