Question

11-(13-?)=7 15-(4+?)=6 7+(14-?)=13

Answer 1

11-(13-9)=7

15-(4+5)=6

7+(14-8)=13

Answer 2

11-(13-9)=11-4=7 

15-(4+5)=15-9=6

7+(14-8)=7+6=13