Question

daca x/y = 3/5 calculati 3x+7y/4x+2y

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Answer 1

x/y=3/5 => 5x=3y => y=5x/3
4x+2y=4x+10x/3=(12x+10x)/3=22x/3
3x+7y=3x+35x/3=(9x+35x)/3=44x/3

3x+7/4x+2y=(44x/3)/(22x/3)=(44x/3)*(3/22x)=44x/22x=44/22=2

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Answer 2

$\Rightarrow\;\;\frac{x}{3}=\frac{y}{5}\;=k\;\Rightarrow\;x=3k\;si\;y=5k\\ \\ inlocuim\;si\;obtinem:\\ \\ \frac{3\cdot3k+7\cdot5k}{4\cdot3k+2\cdot5k}=\frac{44k}{22k}=2$