Tìm số hữu tỉ x, biết: x - 3/4 = 2 1/7

a)Tìm số hữu tỉ \(x\), biết: \(x - \frac{3}{4} = 2\frac{1}{7}\)

 \(x - \frac{3}{4} = \frac{{15}}{7}\)

 \(x = \frac{{15}}{7} + \frac{3}{4}\)

 \(x = \frac{{60}}{{28}} + \frac{{21}}{{28}}\)

 \(x = \frac{{81}}{{28}}\)

b)\(\frac{8}{5} + \frac{2}{5}x = 0,25\).

 \(\frac{2}{5}x = \frac{1}{4} - \frac{8}{5}\)

 \(\frac{2}{5}x = \frac{{ - 27}}{{20}}\)

 \(x = \frac{{ - 27}}{{20}}:\frac{2}{5}\)

 \[x = \frac{{ - 27}}{8}\]