X2-40x+360=0

Solution for X2-40x+360=0 equation:

X2-40X+360=0

We add all the numbers together, and all the variables

X^2-40X+360=0

a = 1; b = -40; c = +360;
Δ = b2-4ac
Δ = -402-4·1·360
Δ = 160
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:

$\sqrt{\Delta}=\sqrt{160}=\sqrt{16*10}=\sqrt{16}*\sqrt{10}=4\sqrt{10}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-40)-4\sqrt{10}}{2*1}=\frac{40-4\sqrt{10}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-40)+4\sqrt{10}}{2*1}=\frac{40+4\sqrt{10}}{2}
$