Question

daca x/y=3/5 calculati folosind proprietati derivate , valorile rapoartelor: 5x-4y/4x-5y

Answer 1

$\it \dfrac{x}{y} = \dfrac{3}{5} \Rightarrow \dfrac{x}{y} = \dfrac{6}{10} \Rightarrow \dfrac{x}{y} = 0,6 \Rightarrow x = 0,6 y\ \ \ \ (*)$


$\it \dfrac{5x-4y}{4x-5y} \stackrel{(*)}{=} \dfrac{5\cdot0,6y-4y}{4\cdot0,6y-5y}=\dfrac{3y-4y}{2,4y-5y} = \dfrac{-y}{-2,6y} = \dfrac{10}{26} =\dfrac{5}{13}.$