1.Daca x + y/2x + y=4/5,atunci x/y=.................... 2.Daca 3x +4y/2x + y=7/3,atunci x/y=................ ........................................................................3.Daca 6x + 4y/5x+2y=3/2,atunci x/y=.........................4.Daca 5x-4y/2x-y=7/3,2x≠ y,atunci x/y=.........................................

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Răspunsuri

2014-08-28T18:53:33+03:00
1.(x+y) /(2x+y) = 4/5       5(x+y) = 4(2x+y)       5x+5y = 8x +4y     y = 3x ⇒x/y = x/3x =!/3  2. (3x+4y) /(2x+y) = 7/3   3(3x+4y) = 7(2x+y)   9x+12y =14x+7y⇒5y=5x⇒x=y⇒  x/y=1/1 3. (6x+4y)/(5x+2y) =3/2   2(6x+4y)=3(5x+2y)  12x+8y=15x+6y ⇒2y=3x⇒x/y=x/(3x/2)=2/3 4. (5x-4y)/(2x-y)=7/3  3(5x-4y)=7(2x-y)   15x-12y=14x-7y⇒x=5y⇒x/y=5y/y =5/1
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