Question

calcule o valor da expressão me ajudem na A e na B​

Answer 1

Respostas:

$a)\,\,\boldsymbol{-\dfrac{2}{5}}\qquad\text{e}\qquad b)\,\,\boldsymbol{\dfrac{179}{110}}$

Explicação passo-a-passo:

$a)\,\,\dfrac{2}{5}+\left(-\dfrac{2}{7}\right)\div\left(\dfrac{5}{14}\right)=\dfrac{2}{5}+\dfrac{-\frac{2}{7}}{\frac{5}{14}}=\dfrac{2}{5}-\dfrac{2.14}{7.5}=\\\\\\=\dfrac{2}{5}-\dfrac{28}{35}=\dfrac{2}{5}-\dfrac{4}{5}=\dfrac{2-4}{5}=\boldsymbol{-\dfrac{2}{5}}\checkmark$

$b)\,\,\left[\left(-\dfrac{1}{5}\right)\div\left(-\dfrac{1}{7}\right)-\left(-\dfrac{2}{11}\right)\div\left(\dfrac{4}{5}\right)\right]=\\\\\\=\left(\dfrac{-\frac{1}{5}}{-\frac{1}{7}}-\dfrac{-\frac{2}{11}}{\frac{4}{5}}\right)=\left(\dfrac{-1.7}{-5.1}-\dfrac{-2.5}{11.4}\right)=\\\\\\=\dfrac{7}{5}+\dfrac{10}{44}=\dfrac{7.44+5.10}{220}=\dfrac{308+50}{220}==\dfrac{358}{220}=\boldsymbol{\dfrac{179}{110}}\checkmark$

É isso!! :)