Resposta:
[tex]a)( - 4) \times ( - \frac{7}{8} ) = + \frac{28 \div 4}{8 \div 4} = \frac{7}{2} [/tex]
[tex]b)( - 6.4) \times (3.5) = 22.4 \\ ou \\ = ( - \frac{64}{10}) \times ( + \frac{35}{10} ) = - \frac{2240 \div 20}{100 \div 20} = \frac{112}{5} [/tex]
[tex]c)( - \frac{2}{1} ) \times ( - \frac{3}{4} ) \times ( - \frac{1}{7} ) = - \frac{6 \div 2}{28 \div 2} = \frac{3}{14} [/tex]
[tex]d)( - \frac{7}{10} ) \times ( + \frac{3}{7} ) \times ( - \frac{5}{9} ) = \frac{105}{630} [/tex]
[tex]e)( + 5.5) \times ( - 1.1) \times ( - 0.66) = + 3.993 \\ ou \\ ( \frac{55}{10} ) \times ( - \frac{11}{10} ) \times ( - \frac{66}{100} ) = \frac{39930}{10000} [/tex]
[tex]f)( - 1.45) \times ( - 1.4) \times ( - 0.8) = - 1.624 \\ ou \: \: \: \\ ( - \frac{145}{100} ) \times ( - \frac{14}{10} ) \times ( - \frac{8}{10} ) = - \frac{16240}{10000} [/tex]
Boa sorte
