№5. При каких значениях х равенство будет верным? 1) x 3 = 8 12 2) 3 x = 18 30 3) 4 9 = x 81 4) 3 14 = 15 x

Ответ: 1) x=2; 2) x=5; 3) x=36; 4) x=70

Решение:

1) \(\frac{x}{3} = \frac{8}{12}\)

\(x = \frac{8 \cdot 3}{12} = \frac{24}{12} = 2\)

2) \(\frac{3}{x} = \frac{18}{30}\)

\(x = \frac{3 \cdot 30}{18} = \frac{90}{18} = 5\)

3) \(\frac{4}{9} = \frac{x}{81}\)

\(x = \frac{4 \cdot 81}{9} = \frac{324}{9} = 36\)

4) \(\frac{3}{14} = \frac{15}{x}\)

\(x = \frac{14 \cdot 15}{3} = \frac{210}{3} = 70\)

Ответ: 1) x=2; 2) x=5; 3) x=36; 4) x=70