Question

Fie proportia x pe 2 = y pe 7 .determinati valoarea raportului 9x-y pe x+2y .

Answer 1

$\frac{x}{2}$=$\frac{y}{7}$ =>7x=2y => x=$\frac{2y}{7}$

$\frac{9x-y}{x+2y}$=$\frac{9( \frac{2y}{7}-y) }{x+2y}= \frac{9(- \frac{5y}{7}) }{ \frac{2y}{7} +2y} = \frac{-45y}{7} * \frac{7}{16y} = \frac{-45y}{16y}$