Question

sendo x = 1,444... e y= 6.3.. calcule o valor de:
3/7 x - 5/21 y

Answer 1

Olá, Ian.

$\frac37 x - \frac5{21} y=\frac37 \cdot1,444... - \frac5{21} \cdot6,333...=\frac37 \cdot (1+\frac49) - \frac5{21} \cdot (6+\frac{\not3\,1}{\not9\,3})=\\\\ =\frac37\cdot(\frac{9+4}9) - \frac5{21} \cdot (\frac{18+1}3)=\frac{13}{21}-\frac{95}{63}=\frac{39-95}{63}=\boxed{-\frac{56}{63}}$