[Toán 7]Tim x, y

E

eye_smile

Ta có: $\dfrac{1}{x} + \dfrac{1}{y} = \dfrac{1}{8}\left( {x < y} \right)$
$ \leftrightarrow \dfrac{{x + y}}{{xy}} = \dfrac{1}{8}$
$ \leftrightarrow 8\left( {x + y} \right) = xy$
$ \leftrightarrow \left( {x - 8} \right)\left( {y - 8} \right) = 64$
Đến đây thì dễ rồi nhé bạn:p
 
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