X2+8x-20x=5

Solution for X2+8x-20x=5 equation:

X2+8X-20X=5

We move all terms to the left:

X2+8X-20X-(5)=0

We add all the numbers together, and all the variables

X^2-12X-5=0

a = 1; b = -12; c = -5;
Δ = b2-4ac
Δ = -122-4·1·(-5)
Δ = 164
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:

$\sqrt{\Delta}=\sqrt{164}=\sqrt{4*41}=\sqrt{4}*\sqrt{41}=2\sqrt{41}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-2\sqrt{41}}{2*1}=\frac{12-2\sqrt{41}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+2\sqrt{41}}{2*1}=\frac{12+2\sqrt{41}}{2}
$