Question

6-{-9+[-1+14-(8+17-12)]

Answer 1

6-{-9+[-1+14-13]
6-{-9+0]
6-(-9)
6+9
15

Answer 2

6-{-9+[-1+14-(8+17-12)]}
6-{-9+[-1+14-(25-12)]}
6-{-9+[-1+14-(13)]}
6-{-9+[-1+14-13]}
6-{-9+[13-13]}
6-{-9+[0]}
6-{-9}
6+9 = 15
espero ter ajudado!