\(x\cdot x=\dfrac{4}{9}\Rightarrow x^2=\dfrac{4}{9}\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=-\dfrac{2}{3}\end{matrix}\right.\)
x = \(\dfrac{2}{3}\)
Vì x . x = x2
và \(\dfrac{4}{9}=\dfrac{2}{3}\) nên x = \(\dfrac{2}{3}\)
\(x\times x=\dfrac{4}{9}\rightarrow x^2=\dfrac{4}{9}\)
mà \(\dfrac{4}{9}=\left(\dfrac{2}{3}\right)^2\)
\(\rightarrow x=\dfrac{2}{3}\)
\(x.x=\dfrac{4}{9}\)
\(\Rightarrow x^2\) \(=\left(\dfrac{2}{3}\right)^2\)
\(\Rightarrow x=\dfrac{2}{3}\)
Ta có: \(x^2=\dfrac{4}{9}\)
nên \(x\in\left\{\dfrac{2}{3};-\dfrac{2}{3}\right\}\)
