\(5-9x^2=0\)
\(\Leftrightarrow9x^2=5\)
\(\Leftrightarrow x^2=\dfrac{5}{9}\)
\(\Rightarrow\left[{}\begin{matrix}x=\sqrt{\dfrac{5}{9}}\\x=-\sqrt{\dfrac{5}{9}}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{\sqrt{5}}{3}\\x=-\dfrac{\sqrt{5}}{3}\end{matrix}\right.\)
\(x^2+x+\dfrac{1}{4}=0\)
\(\Leftrightarrow\left(x+\dfrac{1}{2}\right)^2=0\)
\(\Rightarrow x+\dfrac{1}{2}=0\Rightarrow x=-\dfrac{1}{2}\)
Học tốt nha<3
\(5-9x^2=0\\ 9x^2=5\\ x^2=\dfrac{5}{9}\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{-\sqrt{5}}{3}\\x=\dfrac{\sqrt{5}}{3}\end{matrix}\right.\)
\(x^2+x+\dfrac{1}{4}=0\\ \left(x+\dfrac{1}{2}\right)^2=0\\ x+\dfrac{1}{2}=0\\ x=\dfrac{-1}{2}\)
