x2-72x+225=0

Solution for x2-72x+225=0 equation:

x2-72x+225=0

We add all the numbers together, and all the variables

x^2-72x+225=0

a = 1; b = -72; c = +225;
Δ = b2-4ac
Δ = -722-4·1·225
Δ = 4284
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:

$\sqrt{\Delta}=\sqrt{4284}=\sqrt{36*119}=\sqrt{36}*\sqrt{119}=6\sqrt{119}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-72)-6\sqrt{119}}{2*1}=\frac{72-6\sqrt{119}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-72)+6\sqrt{119}}{2*1}=\frac{72+6\sqrt{119}}{2}
$