Solve the equations and write down the answers.

Решение:

1. \( x : 30 = 175 - 80 \)
• \( x : 30 = 95 \)
• \( x = 95 \cdot 30 \)
• \( x = 2850 \)
2. \( 5 \cdot x = 300 - 85 \)
• \( 5 \cdot x = 215 \)
• \( x = 215 : 5 \)
• \( x = 43 \)
3. \( x : 30 = 95 \)
• \( x = 95 \cdot 30 \)
• \( x = 2850 \)
4. \( x = 15 \cdot 30 \)
• \( x = 450 \)

Ответ: x = 2850; x = 43; x = 2850; x = 450.