Question

Daca x/y=2/5, atunci valoarea raportului 10x-14y+8/5x+3y-4 este ...

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Answer 1

 

$\displaystyle\bf\\ \frac{x}{y}=\frac{2}{5}\\\\x=\frac{2y}{5}\\\\\frac{10x-14y+8}{5x+3y-4}=\\\\\\=\frac{10\cdot\dfrac{2y}{5}-14y+8}{5\cdot\dfrac{2y}{5}+3y-4}=\\\\\\=\frac{4y-14y+8}{2y+3y-4}=\\\\\\=\frac{-10y+8}{5y-4}=\\\\\\=\frac{-2(5y-4)}{5y-4}=-2\cdot\frac{5y-4}{5y-4}=-2\cdot1=\boxed{\bf-2}$