Найдите х из пропорции:

Решим пропорции: a) \(\frac{x}{-1,4} = \frac{-7,3}{-2,8}\) \(x = \frac{-7,3 \cdot (-1,4)}{-2,8} = \frac{7,3 \cdot 1,4}{2,8} = \frac{7,3}{2} = 3,65\) б) \(\frac{-8,4}{105} = \frac{-12,6}{x}\) \(x = \frac{-12,6 \cdot 105}{-8,4} = \frac{12,6 \cdot 105}{8,4} = \frac{126 \cdot 105}{84} = \frac{63 \cdot 105}{42} = \frac{3 \cdot 105}{2} = \frac{315}{2} = 157,5\) в) \(\frac{-2,5x}{14} = \frac{1\frac{1}{7}}{-30}\) \(\frac{-2,5x}{14} = \frac{\frac{8}{7}}{-30}\) \(-2,5x = \frac{14 \cdot \frac{8}{7}}{-30} = \frac{2 \cdot 8}{-30} = \frac{16}{-30} = -\frac{8}{15}\) \(x = -\frac{8}{15} : (-2,5) = \frac{8}{15} : \frac{5}{2} = \frac{8}{15} \cdot \frac{2}{5} = \frac{16}{75}\) г) \(\frac{-7\frac{1}{2}}{4\frac{1}{2}} = \frac{x}{\frac{3}{25}}\) \(\frac{-\frac{15}{2}}{\frac{9}{2}} = \frac{x}{\frac{3}{25}}\) \(x = \frac{-\frac{15}{2} \cdot \frac{3}{25}}{\frac{9}{2}} = -\frac{15}{2} \cdot \frac{3}{25} \cdot \frac{2}{9} = -\frac{3}{1} \cdot \frac{3}{25} \cdot \frac{1}{9} = -\frac{9}{225} = -\frac{1}{25} = -0,04\)