Bài 9 Tìm x, biết:
a) x + \(\frac{1}{3} = \frac{3}{4}\)
b) x - \(\frac{2}{5} = \frac{5}{7}\)
d) \(\frac{4}{7} - x = \frac{1}{3}\)
Advertisements (Quảng cáo)
a) x + \(\frac{1}{3} = \frac{3}{4}\) => x = \(\frac{3}{4} - \frac{1}{3} = \frac{9}{12} - \frac{4}{12} = \frac{5}{12}\)
b) x - \(\frac{2}{5} = \frac{5}{7}\) => x = \(\frac{5}{7} + \frac{2}{5} = \frac{25}{35} + \frac{14}{35}= \frac{39}{35} = 1\frac{4}{35}\)
c) -x - \(\frac{2}{3}\) = \(- \frac{6}{7}\) => \(\frac{-2}{3} + \frac{6}{7} = x => x = -\frac{14}{21} + \frac{18}{21} = \frac{4}{21}\)
d) \(\frac{4}{7} - x = \frac{1}{3}\) => \(\frac{4}{7} - \frac{1}{3} = x => x = \frac{12}{21} - \frac{7}{21} = \frac{5}{21}\)