Question

Eu não sei essa operação no conjunto dos números racionais  preciso de ajuda...
 1    +    3    ×     2    ÷  4   =
  5          4           3

   3     +      2     ÷     1     +  3  =
  4             3             5

(  4    +    2  )  ÷    1   =
(  3          7 )        2

  1    ÷  (  3    -    2  )  =
 3        (  5         6   )





  

Answer 1

1) $\dfrac{1}{5}+\dfrac{3}{4}\times\dfrac{2}{3}\div4=\dfrac{1}{5}+\dfrac{1}{2}\div4=\dfrac{1}{5}+\dfrac{1}{8}=\dfrac{8+5}{40}=\dfrac{13}{40}$


2) $\dfrac{3}{4}+\dfrac{2}{3}\div\dfrac{1}{5}+3=\dfrac{3}{4}+\dfrac{2}{3}\cdot5+3=\dfrac{3}{4}+\dfrac{10}{3}+3=\dfrac{9+40+36}{12}=\dfrac{85}{12}$


3) $\left(\dfrac{4}{3}+\dfrac{2}{7}\right)\div\dfrac{1}{2}=\left(\dfrac{28+6}{21}\right)\div\dfrac{1}{2}=\dfrac{34}{21}\div\dfrac{1}{2}=\dfrac{68}{21}$

4) $\dfrac{1}{3}\div\left(\dfrac{3}{5}-\dfrac{2}{6}\right)=\dfrac{1}{3}\div\left(\dfrac{3}{5}-\dfrac{1}{3}\right)=\dfrac{1}{3}\div\left(\dfrac{9-5}{15}\right)$

$=\dfrac{1}{3}\div\dfrac{4}{15}=\dfrac{1}{3}\cdot\dfrac{15}{4}=\dfrac{15}{12}=\dfrac{5}{4}$.