\(x^2-1=\frac{7}{9}\)
\(\Rightarrow x^2=\frac{7}{9}+1\)
\(\Rightarrow x^2=\frac{16}{9}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{4}{3}\\x=\left(-\frac{4}{3}\right)\end{cases}}\)
\(x^2-1=\frac{7}{9}\)
\(x^2\) \(=\frac{7}{9}+1\)
\(x^2\) \(=\frac{16}{9}\)
\(\Rightarrow x\orbr{\begin{cases}\frac{4}{3}\\\frac{-4}{3}\end{cases}}\)
Vây...
\(^{x^2}\)-1=\(\frac{7}{9}\)
\(^{x^2}\)=\(\frac{7}{9}\)+1
\(^{x^2}\)=\(\frac{16}{9}\)
=>\(\orbr{\begin{cases}x=\frac{4}{3}\\x=\frac{-4}{3}\end{cases}}\)
VẬY x=\(\frac{4}{3}\)hoặc x=\(\frac{-4}{3}\)
