Вариант 2 1. Решите уравнение: 1) 6:5=x: 75; 3) x/0.8=15/4 ; 2) a:1 7/50=5 5/57: 1/2; 4) 5-y/4=3/7.

Решим уравнения:

1) $$6:5 = x:75$$

$$x = \frac{6 \cdot 75}{5}$$

$$x = \frac{6 \cdot 15}{1}$$

$$x = 90$$

Ответ: 90

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2) $$a:1\frac{7}{50} = 5\frac{5}{57}:\frac{1}{2}$$

$$a:\frac{57}{50} = \frac{290}{57}:\frac{1}{2}$$

$$a:\frac{57}{50} = \frac{290}{57} \cdot 2$$

$$a = \frac{290 \cdot 2 \cdot 57}{57 \cdot 50}$$

$$a = \frac{290 \cdot 2}{50}$$

$$a = \frac{29 \cdot 2}{5}$$

$$a = \frac{58}{5} = 11\frac{3}{5} = 11.6$$

Ответ: 11.6

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3) $$\frac{x}{0.8} = \frac{15}{4}$$

$$x = \frac{15 \cdot 0.8}{4}$$

$$x = \frac{15 \cdot 0.2}{1}$$

$$x = 3$$

Ответ: 3

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4) $$\frac{5-y}{4} = \frac{3}{7}$$

$$5-y = \frac{3 \cdot 4}{7}$$

$$5-y = \frac{12}{7}$$

$$y = 5 - \frac{12}{7}$$

$$y = \frac{35}{7} - \frac{12}{7}$$

$$y = \frac{23}{7} = 3\frac{2}{7}$$

Ответ: 3 2/7