\(x^2-5x+3=0\)
\(\Leftrightarrow x=\dfrac{-\left(-5\right)\pm\sqrt{\left(-5\right)^2-4\cdot1\cdot3}}{2\cdot1}\)
\(\Leftrightarrow x=\dfrac{5\pm\sqrt{25-12}}{2}\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5+\sqrt{13}}{2}\\x=\dfrac{5-\sqrt{13}}{2}\end{matrix}\right.\)