Matemática
nicolietavares
15

Efetue os cálculos indicados nas expressões numéricas: a) 3/5 x (1/3 - 1/2) b) - 2/9 x (1/4 + 1/5) , c)2/5 - 8/3 x (1/2)³ +3/4 , d) -7/9 x (2/3 - 4/5 x 5)

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a) Temos que:   [latex]\dfrac{3}{5}\times\left(\dfrac{1}{3}-\dfrac{1}{2}\right)[/latex]   [latex]=\dfrac{3}{5}\times\left(\dfrac{2-3}{6}\right)[/latex]   [latex]=\dfrac{3}{5}\times\dfrac{-1}{6}=\dfrac{-3}{30}=\dfrac{-1}{10}[/latex] b) Temos que:   [latex]\dfrac{-2}{9}\times\left(\dfrac{1}{4}+\dfrac{1}{5}\right)[/latex]   [latex]=\dfrac{-2}{9}\times\left(\dfrac{5+4}{20}\right)[/latex]   [latex]=\dfrac{-2}{9}\times\dfrac{9}{20}=\dfrac{-18}{180}=\dfrac{-1}{10}[/latex]   c) Temos que:   [latex]\dfrac{2}{5}-\dfrac{8}{3}\times\left(\dfrac{1}{2}\right)^3+\dfrac{3}{4}[/latex]   [latex]=\dfrac{2}{5}-\dfrac{8}{3}\times\dfrac{1}{8}+\dfrac{3}{4}[/latex]   [latex]=\dfrac{2}{5}-\dfrac{1}{3}+\dfrac{3}{4}[/latex]   [latex]=\dfrac{24-20+45}{60}=\dfrac{49}{60}[/latex] d) Temos que:   [latex]\dfrac{-7}{9}\times\left(\dfrac{2}{3}-\dfrac{4}{5}\times5\right)[/latex]   [latex]=\dfrac{-7}{9}\times\left(\dfrac{2}{3}-4\right)[/latex]   [latex]=\dfrac{-7}{9}\times\left(\dfrac{2-12}{12}\right)[/latex]   [latex]=\dfrac{-7}{9}\times\dfrac{-10}{12}[/latex]   [latex]=\dfrac{70}{108}=\dfrac{35}{54}[/latex]

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