Question

tìm x là số nguyên am \(\dfrac{9x}{4}=\dfrac{16}{x}\)

Answer 1

\(\dfrac{9x}{4}=\dfrac{16}{x}\)

\(\Leftrightarrow9x.x=16.4\)

\(\Leftrightarrow9x^2=64\)

\(\Leftrightarrow x^2=\dfrac{64}{9}\)

\(\Leftrightarrow x=\sqrt{\dfrac{64}{9}}\)

​\(\Leftrightarrow x=\dfrac{8}{3}\)​

Vậy \(x=\dfrac{8}{3}\)

Answer 2

Ta có : 9x / 4 = 16 / x

<=> 9x² = 16.4 = 64

<=> x² = 64/9 = (8 /3)²

<=> x = 8/3

Vậy ko có x thõa mãn x<0 x thuộc Z