Question

Giúp em với ạ!

Answer 1

\(x^2=\dfrac{4}{9} \)

Mà: \(\left(-\dfrac{2}{3}\right)^2=\left(\dfrac{2}{3}\right)^2=\dfrac{4}{9}\)

=> \(\left[{}\begin{matrix}x=-\dfrac{2}{3}\\x=\dfrac{2}{3}\end{matrix}\right.\)

Vậy \(S=\left\{-\dfrac{2}{3};\dfrac{2}{3}\right\}\)

Answer 2

Đáp án D : \(\dfrac{2}{3}\)   hoặc  \(\dfrac{-2}{3}\)

Answer 3

\(x=+-\sqrt{\dfrac{4}{9}}=+-\dfrac{2}{3}\)

=> câu D

Answer 4

Chọn D nhé bạn