Tìm x: \(\dfrac{-2}{3}x=\left(\dfrac{-1}{3}\right)^2\) \(x=\dfrac{1}{6}\) \(x=\dfrac{-2}{27}\) \(x=-\dfrac{1}{6}\) \(x=\dfrac{2}{27}\)
Cho \(\sqrt{x+1}=2\). Tìm \(x^2.\) 9 3 81 27 Hướng dẫn giải: \(\sqrt{x+1}=2\) \(\Leftrightarrow x+1=2^2\) \(\Leftrightarrow x+1=4\) \(\Leftrightarrow x=3\). Vậy \(x^2=3^2=9\).
