Question

alguém pode me ajudar???????pfvr ???????​

Answer 1

Explicação passo-a-passo:

Boa noite Iolanda V●ᴥ●V

Devemos ficar atentos ao jogo de sinais

$- - = +$

$- + = -$

$+ - = -$

$+ + = +$

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Não devemos esquecer também, que frações com denominadores iguais, permanece os denominadores, e soma os numeradores.

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Resolvendo exercício=>

$1)$

$( - \dfrac{1}{3} ) + ( - \dfrac{2}{3} )$

$- \dfrac{1}{3} - \dfrac{2}{3}$

$\dfrac{ - 1 - 2}{3}$

$- \dfrac{3}{3}$

$- 1$

$2)$

$( + \dfrac{4}{10} ) - ( - \dfrac{2}{10} )$

$\dfrac{4}{10} + \dfrac{2}{10}$

$\dfrac{4 + 2}{10}$

$\dfrac{6}{10}$

$\dfrac{6 {}^{ \div 2} }{10 {}^{ \div 2} }$

$\dfrac{3}{5}$

$3)$

$( - \dfrac{2}{5} ) - ( + \dfrac{2}{5} )$

$- \dfrac{2}{5} - \dfrac{2}{5}$

$\dfrac{ - 2 - 2}{5}$

$- \dfrac{4}{5}$

$4)$

$( + \dfrac{2}{9} ) + ( - \dfrac{3}{9} )$

$+ \dfrac{2}{9} - \dfrac{3}{9}$

$\dfrac{2 - 3}{9}$

$- \dfrac{1}{9}$

$5)$

$( - \dfrac{10}{12} ) - ( + \dfrac{5}{12} )$

$- \dfrac{ 10}{12} - \dfrac{5}{12}$

$\dfrac{ - 10 - 5}{12}$

$- \dfrac{ 15}{12}$

$- \dfrac{15 {}^{ \div 3} }{12 {}^{ \div 3} }$

$- \dfrac{5}{4}$

$6)$

$( + \dfrac{7}{8} ) + ( + \dfrac{5}{8} )$

$\dfrac{7}{8} + \dfrac{5}{8}$

$\dfrac{7 + 5}{8}$

$\dfrac{12}{8}$

$\dfrac{12 {}^{ \div 4} }{8 {}^{ \div 4} }$

$\dfrac{3}{2}$

$7)$

$( - \dfrac{1}{6} ) - ( - \dfrac{2}{6} )$

$- \dfrac{1}{6} + \dfrac{2}{6}$

$\dfrac{ - 1 + 2}{6}$

$\dfrac{1}{6}$

$8)$

$( + \dfrac{20}{35} ) + ( - \dfrac{12}{35} )$

$\dfrac{20}{35} - \dfrac{12}{35}$

$\dfrac{20 - 12}{35}$

$\dfrac{8}{35}$

$9)$

$( - \dfrac{16}{19} ) - ( - \dfrac{16}{19} )$

$- \dfrac{16}{19} + \dfrac{16}{19}$

$\dfrac{ - 16 + 16}{19}$

$\dfrac{0}{19}$

$0$

$10)$

$( + \dfrac{14}{15} ) + ( - \dfrac{5}{15} )$

$+ \dfrac{14}{15} - \dfrac{5}{15}$

$\dfrac{14 - 5}{15}$

$\dfrac{9}{15}$

$\dfrac{9 {}^{ \div 3} }{15 {}^{ \div 3} }$

$\dfrac{3}{5}$

$11)$

$( - \dfrac{1}{5} ) \times ( - \dfrac{4}{3} )$

$\dfrac{4}{15}$

$12)$

$( + \dfrac{4}{9} ) \times ( - \dfrac{7}{5} )$

$- \dfrac{28}{45}$

$13)$

$( - \dfrac{3}{2} ) \times ( \dfrac{5}{ 7} )$

$- \dfrac{15}{14}$

$14)$

$( - \dfrac{5}{8} ) \times ( - \dfrac{4}{3} )$

$\dfrac{20}{24}$

$\dfrac{20 {}^{ \div 4} }{24 {}^{ \div 4} }$

$\dfrac{5}{6}$

$15)$

$( - \dfrac{3}{5} ) \times ( - \dfrac{7}{4} )$

$\dfrac{21}{20}$

Espero ter ajudado!