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  • Utilizator Brainly
2014-09-05T11:50:04+03:00
 \frac{2x+5y}{x+y} =4,5

 \frac{2x+5y}{x+y} = \frac{45}{10}

10*(2x+5y)=45*(x+y)
20x+50y=45x+45y
25x=5y
5x=y

a)x/y=1/5
b)5x/2y=5/2*1/5=1/2
c) \frac{ x^{2}+y^2}{y^2} = \frac{x^2}{y^2} + \frac{y^2}{y^2} =( \frac{x}{y} )^2+1= \frac{1}{25} +1= \frac{26}{25}
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