\( x^{2}-15 x+54=0 \)
\(x = \frac{15 \pm \sqrt{9}}{2}\)
Step 1 :\(x = \frac{-(-15) \pm \sqrt{(-15)^2 - 4 \cdot 1 \cdot 54}}{2 \cdot 1}\)
Step 2 :\(x = \frac{15 \pm \sqrt{225 - 216}}{2}\)
Step 3 :\(x = \frac{15 \pm \sqrt{9}}{2}\)