`x^2 : (-1 1 / 9 ) = -2,5`
`x^2 : [-10] / 9 = [-5] / 2`
`x^2 = [-5] / 2 xx [-10] / 9`
`x^2 = 25 / 9`
`x^2 = (5 / 3)^2` hoặc `x^2 = ([-5] / 3)^2`
`x = 5 / 3` hoặc `x = [-5] / 3`
Vậy `x = 5 / 3` hoặc `x = [-5] / 3`
\(x^2:-1\dfrac{1}{9}=2,5\)
\(x^2:\left(-\dfrac{10}{9}\right)=-\dfrac{5}{2}\)
\(x^2\cdot\left(-\dfrac{9}{10}\right)=-\dfrac{5}{2}\)
\(x^2=\left(-\dfrac{5}{2}\right):\left(-\dfrac{9}{10}\right)\)
\(x^2=\dfrac{25}{9}\)
\(\left[{}\begin{matrix}x^2=\dfrac{25}{9}\\x^2=-\dfrac{25}{9}\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=\dfrac{5^2}{3^2}\\x=-\dfrac{5^2}{3^2}\end{matrix}\right.\)
\(\Rightarrow\) \(x=\left[{}\begin{matrix}\dfrac{5}{3}\\-\dfrac{5}{3}\end{matrix}\right.\)
Vậy \(x=\left[{}\begin{matrix}\dfrac{5}{3}\\-\dfrac{5}{3}\end{matrix}\right.\)