Question

Cho hàm số f(x) = x² - 1 . Tìm x sao cho f(x) = 1

Answer 1

\(f\left(x\right)=x^2-1\)

\(\Leftrightarrow x^2-1=1\)

\(\Leftrightarrow x^2=2\)

\(\Rightarrow x=\pm\sqrt{2}\)

Answer 2

Ta có: \(f\left(x\right)=x^2-1=1\)

\(\Leftrightarrow x^2=2\)

\(\Leftrightarrow x=\sqrt{2}\) và \(x=-\sqrt{2}\)