X(x-8)=-5

Solution for X(x-8)=-5 equation:

X(X-8)=-5

We move all terms to the left:

X(X-8)-(-5)=0

We add all the numbers together, and all the variables

X(X-8)+5=0

We multiply parentheses

X^2-8X+5=0

a = 1; b = -8; c = +5;
Δ = b2-4ac
Δ = -82-4·1·5
Δ = 44
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:

$\sqrt{\Delta}=\sqrt{44}=\sqrt{4*11}=\sqrt{4}*\sqrt{11}=2\sqrt{11}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-2\sqrt{11}}{2*1}=\frac{8-2\sqrt{11}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+2\sqrt{11}}{2*1}=\frac{8+2\sqrt{11}}{2}
$