Решение:
1. \( 69 - (91 - 46) : 3 + 18 \cdot 3 : 4 \)
- \( 91 - 46 = 45 \)
- \( 45 : 3 = 15 \)
- \( 18 \cdot 3 = 54 \)
- \( 54 : 4 = 13.5 \)
- \( 69 - 15 + 13.5 = 54 + 13.5 = 67.5 \)
2. \( (84 : 6 + 75) \cdot 18 \)
- \( 84 : 6 = 14 \)
- \( 14 + 75 = 89 \)
- \( 89 \cdot 18 = 1602 \)
3. \( 75 : 25 \cdot 17 + 2^4 \cdot 3.8 \)
- \( 75 : 25 = 3 \)
- \( 3 \cdot 17 = 51 \)
- \( 2^4 = 16 \)
- \( 16 \cdot 3.8 = 60.8 \)
- \( 51 + 60.8 = 111.8 \)
4. \( 120 : 5 \)
- \( 120 : 5 = 24 \)
5. \( (74 - 45) \cdot 25 \)
- \( 74 - 45 = 29 \)
- \( 29 \cdot 25 = 725 \)
Ответ: 1. 67.5; 2. 1602; 3. 111.8; 4. 24; 5. 725.