8x(x+8)=5

Solution for 8x(x+8)=5 equation:

8x(x+8)=5

We move all terms to the left:

8x(x+8)-(5)=0

We multiply parentheses

8x^2+64x-5=0

a = 8; b = 64; c = -5;
Δ = b2-4ac
Δ = 642-4·8·(-5)
Δ = 4256
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:

$\sqrt{\Delta}=\sqrt{4256}=\sqrt{16*266}=\sqrt{16}*\sqrt{266}=4\sqrt{266}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(64)-4\sqrt{266}}{2*8}=\frac{-64-4\sqrt{266}}{16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(64)+4\sqrt{266}}{2*8}=\frac{-64+4\sqrt{266}}{16}
$