A=[tex]( \frac{14}{6}- \frac{3}{9})× \frac{-3}{4} [/tex]
=[tex] (\frac{14×3}{6×3}- \frac{3×2}{9×2})× \frac{-3}{4} [/tex]
=[tex]( \frac{42}{18}- \frac{6}{18})× \frac{-3}{4} [/tex]
=[tex] \frac{36}{18}× \frac{-3}{4} [/tex]
=[tex] \frac{9×4×(-3)}{9×2×4} [/tex]
=[tex] \frac{-3}{2} [/tex]
B=[tex]( \frac{2}{5})²-2[/tex]
=[tex] \frac{4}{25}-2[/tex]
=[tex] \frac{4}{25}- \frac{2×25}{1×25} [/tex]
=[tex] \frac{4}{25} - \frac{50}{25} [/tex]
=[tex] \frac{-46}{25} [/tex]