Question

TÌm số nguyên x biết ( có các bước giải )

a \(\dfrac{x}{2}\) = \(\dfrac{2}{x}\) ; b \(\dfrac{x}{-5}\) = \(\dfrac{-5}{x}\)

Answer 1

a) \(\dfrac{x}{2}=\dfrac{2}{x}\)

⇔ \(x^2=4\)

⇒ \(\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)

b) \(\dfrac{x}{-5}=\dfrac{-5}{x}\)

⇔ \(x^2=25\)

⇒ \(\left[{}\begin{matrix}x=5\\x=-5\end{matrix}\right.\)

Answer 2

\(a,\Rightarrow x^2=2^2\\ \Rightarrow x=2\\ b,x^2=\left(-5\right)^2\\ \Rightarrow x=-5\)

Answer 3

a: =>x²=4

hay \(x\in\left\{2;-2\right\}\)

b: =>x²=25

hay \(x\in\left\{5;-5\right\}\)