Question

a (-3/4).(+10/7)
b (+2/5).(-5/4)​

Answer 1

Resolvendo:

a)

$( - \frac{3}{4} ) \times ( + \frac{10}{7} ) = \frac{ - 3 \times ( + 10)}{4 \times 7} = - \frac{30}{28} = - \frac{15}{14}$

b)

$( + \frac{2}{5} ) \times ( - \frac{5}{4} ) = \frac{ + 2 \times ( - 5)}{5 \times 4} = - \frac{10}{20} = - \frac{1}{2}$

Espero ter ajudado!