x(x-8)=764

Solution for x(x-8)=764 equation:

x(x-8)=764

We move all terms to the left:

x(x-8)-(764)=0

We multiply parentheses

x^2-8x-764=0

a = 1; b = -8; c = -764;
Δ = b2-4ac
Δ = -82-4·1·(-764)
Δ = 3120
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:

$\sqrt{\Delta}=\sqrt{3120}=\sqrt{16*195}=\sqrt{16}*\sqrt{195}=4\sqrt{195}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-4\sqrt{195}}{2*1}=\frac{8-4\sqrt{195}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+4\sqrt{195}}{2*1}=\frac{8+4\sqrt{195}}{2}
$