Explicación paso a paso:
18 ÷ [ - 5 + ( - 3 × 2 + 5 ) ]
18 ÷ [ - 5 + ( - 6 + 5 ) ]
18 ÷ [ - 5 + ( - 1 ) ]
18 ÷ [ - 5 - 1 ]
18 ÷ [ - 6 ]
- 3
