[tex]\dfrac xy=\dfrac{3125}{10000}\cdot\dfrac 65=\dfrac38\Rightarrow x=\dfrac{3y}{8}[/tex]
In locuim aceasta valoare in fractia pe care trebuie sa o calculam
[tex]\dfrac{19x-7y}{5x+3y}=\dfrac{19\cdot\dfrac{3y}{8}-7y}{5\cdot\dfrac{3y}{8}+3y}=\dfrac{57y-56y}{15y+24y}=\dfrac{1}{39}[/tex]
