в) (7/12 + x) : 7 1/4 = 1/3

в) \((\frac{7}{12} + x) : 7 \frac{1}{4} = \frac{1}{3}\) \((\frac{7}{12} + x) : \frac{29}{4} = \frac{1}{3}\) \(\frac{7}{12} + x = \frac{1}{3} \cdot \frac{29}{4}\) \(\frac{7}{12} + x = \frac{29}{12}\) \(x = \frac{29}{12} - \frac{7}{12}\) \(x = \frac{22}{12}\) \(x = \frac{11}{6} = 1 \frac{5}{6}\)