x2-156x+720=0

Solution for x2-156x+720=0 equation:

x2-156x+720=0

We add all the numbers together, and all the variables

x^2-156x+720=0

a = 1; b = -156; c = +720;
Δ = b2-4ac
Δ = -1562-4·1·720
Δ = 21456
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:

$\sqrt{\Delta}=\sqrt{21456}=\sqrt{144*149}=\sqrt{144}*\sqrt{149}=12\sqrt{149}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-156)-12\sqrt{149}}{2*1}=\frac{156-12\sqrt{149}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-156)+12\sqrt{149}}{2*1}=\frac{156+12\sqrt{149}}{2}
$