Решение:
- \( x : 3 = 100 \)
\( x = 100 \cdot 3 \)
\( x = 300 \) - \( x + 13 = 750 \)
\( x = 750 - 13 \)
\( x = 737 \) - \( x : 15 = 50 \)
\( x = 50 \cdot 15 \)
\( x = 750 \) - \( 333 : x = 111 \)
\( x = 333 : 111 \)
\( x = 3 \) - \( x \cdot 560 = 560 \)
\( x = 560 : 560 \)
\( x = 1 \)
Ответ: 1. 300; 2. 737; 3. 750; 4. 3; 5. 1.