Question

Tìm x biết:\(\dfrac{-x}{4}=\dfrac{-9}{x}\)

Answer 1

\(\dfrac{-x}{4}=\dfrac{-9}{x}\Rightarrow4.\left(-9\right)=x.\left(-x\right)=-36\)

\(\Rightarrow x^2=\left|-36\right|=36\)

\(\Rightarrow x=6\)

Answer 2

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

\(\Rightarrow-x^2=-36\)

\(\Rightarrow x^2=36\)

\(\Rightarrow x=\pm6\)