Question

Tìm x trong các tỉ lệ thức

b) \(\dfrac{-2}{x}=\dfrac{-x}{\dfrac{8}{25}}\)

Answer 1

\(\dfrac{-2}{x}=\dfrac{-x}{\dfrac{8}{25}}\left(x\ne0\right)\\ =>\dfrac{2}{x}=\dfrac{x}{\dfrac{8}{25}}\\ =>x^2=2.\dfrac{8}{25}=\dfrac{16}{25}=\left(\pm\dfrac{4}{5}\right)^2\\ =>x=\pm\dfrac{4}{5}\left(TMDK\right)\)

Answer 2

\(\Leftrightarrow-x^2=-\dfrac{16}{25}\)

=>x=4/5 hoặc x=-4/5