8x^2-5=-20x

Solution for 8x^2-5=-20x equation:

8x^2-5=-20x

We move all terms to the left:

8x^2-5-(-20x)=0

We get rid of parentheses

8x^2+20x-5=0

a = 8; b = 20; c = -5;
Δ = b2-4ac
Δ = 202-4·8·(-5)
Δ = 560
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:

$\sqrt{\Delta}=\sqrt{560}=\sqrt{16*35}=\sqrt{16}*\sqrt{35}=4\sqrt{35}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-4\sqrt{35}}{2*8}=\frac{-20-4\sqrt{35}}{16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+4\sqrt{35}}{2*8}=\frac{-20+4\sqrt{35}}{16}
$