Question

Tìm x biết -4/x=-x/9   giúp mik với ak

Answer 1

\(\Leftrightarrow x^2=36\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-6\end{matrix}\right.\)

Answer 2

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

\(\Rightarrow x.x=\left(-4\right).\left(-9\right)\)

\(\Rightarrow x^2=36\)

\(\Rightarrow x^2=6^2hoac\left(-6\right)^2\)

\(\Rightarrow x\in\left\{6;-6\right\}\)