Respostas

2014-05-18T15:12:33-03:00
(-1) . [1/2 - (- 1/5) . (-3/2)] + (-2/7) . (-0,7) = 
-1[ \frac{1}{2} -(- \frac{1}{5} )(- \frac{3}{2} )]+(- \frac{2}{7} )( -\frac{7}{10} )= \\ 
-1[ \frac{1}{2} -(\frac{3}{10} )]+(- \frac{14}{70} )= \\ 
-1[ \frac{5-3}{10}]-\frac{14}{70}= \\ 
-1[ \frac{2}{10}]-\frac{14}{70}= \\ 
-\frac{2}{10} - \frac{ 14}{70}= \\
-\frac{1}{5} - \frac{1}{5}= \\
- \frac{2}{5}

Espero ter ajudado, bons estudos ;)
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