x^2+54=18x

Solution for x^2+54=18x equation:

x^2+54=18x

We move all terms to the left:

x^2+54-(18x)=0

a = 1; b = -18; c = +54;
Δ = b2-4ac
Δ = -182-4·1·54
Δ = 108
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{108}=\sqrt{36*3}=\sqrt{36}*\sqrt{3}=6\sqrt{3}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-18)-6\sqrt{3}}{2*1}=\frac{18-6\sqrt{3}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-18)+6\sqrt{3}}{2*1}=\frac{18+6\sqrt{3}}{2}
$