Question

Vă rog rezolvați complet supunctele.
1. Efectuați înmulțirile:

Answer 1

$a) \\ \\ ( - \frac{3}{8}) \times ( + \frac{5}{7}) = - \frac{3}{8} \times \frac{5}{7} = - \frac{3 \times 5}{8 \times 7} = - \frac{15}{56}$

$b) \\ \\ ( - \frac{2}{5}) \times ( + \frac{4}{11}) = - \frac{2}{5} \times \frac{4}{11} = - \frac{2 \times 4}{5 \times 11} = - \frac{8}{55}$

$c) \\ \\ ( - \frac{3}{4}) \times ( + \frac{9}{25}) = - \frac{3}{4} \times \frac{9}{25} = - \frac{3 \times 9}{4 \times 25} = - \frac{27}{100}$

$d) \\ \\ ( - \frac{4}{7}) \times ( - \frac{21}{16}) = \frac{ - 4 \times - 21}{7 \times 16} = { \frac{84}{112} }^{(28} = \frac{3}{4}$

$e) \\ \\ ( - \frac{8}{15}) \times ( + 3 \frac{3}{4}) = ( - \frac{8}{15} ) \times \frac{9}{4} = - \frac{8}{15} \times \frac{9}{4} = - \frac{2}{5} \times 3 = - \frac{2}{5} \times \frac{3}{1} = - \frac{2 \times 3}{5 \times 1} = - \frac{6}{5}$

$f) \\ \\ ( - \frac{4}{15}) \times ( + \frac{9}{8}) \times ( - \frac{10}{21}) = - \frac{4}{15} \times \frac{9}{8} \times \frac{ - 10}{21} = - \frac{4 \times 9 \times - 10}{15 \times 8 \times 21} = - \frac{ - 360}{2520} = - ( - \frac{360}{2520}) = - ( - \frac{1}{7}) = \frac{1}{7}$