1. Решите уравнения, используя основное свойство пропорции: 1. x/4 = 10/5 2. 6/x = 12/8 3. x/7 = 9/3 4. 5/x = 15/6

Решение:

1. \[\frac{x}{4} = \frac{10}{5}\] \[5x = 4 \cdot 10\] \[5x = 40\] \[x = \frac{40}{5}\] \[x = 8\]
2. \[\frac{6}{x} = \frac{12}{8}\] \[6 \cdot 8 = 12x\] \[48 = 12x\] \[x = \frac{48}{12}\] \[x = 4\]
3. \[\frac{x}{7} = \frac{9}{3}\] \[3x = 7 \cdot 9\] \[3x = 63\] \[x = \frac{63}{3}\] \[x = 21\]
4. \[\frac{5}{x} = \frac{15}{6}\] \[5 \cdot 6 = 15x\] \[30 = 15x\] \[x = \frac{30}{15}\] \[x = 2\]

Ответ: 1. x=8, 2. x=4, 3. x=21, 4. x=2