Question

pls solve me this question​

Answer 1

Answer:

1) 11 replaces question mark.

In case 1

15-12=3 , 10-9=1

3+1=4

In case 2

28-12=16 , 16-20=-4

16+(-4)=16-4=12

In case 3

23-11=12 , 15-16=-1

12+(-1)=12-1=11