Tính: a) 3/4 - 7/5

a) \(\frac{3}{4} - \frac{7}{5}:\frac{{14}}{{25}}\)

\( = \frac{3}{4} - \frac{7}{5}\,\,.\,\,\frac{{25}}{{14}}\)

\( = \frac{3}{4} - \,\frac{5}{2} = \frac{{ - 7}}{4}\)

b) \({\left( {\frac{{ - 3}}{2}} \right)^2} + \left( {\frac{1}{2} - \frac{2}{3}} \right) \cdot \frac{3}{4}\)

\( = \frac{9}{4} + \frac{{ - 1}}{6} \cdot \frac{3}{4}\)

\( = \frac{9}{4} + \frac{{ - 1}}{8} = \frac{{17}}{8}\)