-10x^2+64x+100=0

Solution for -10x^2+64x+100=0 equation:

-10x^2+64x+100=0

a = -10; b = 64; c = +100;
Δ = b2-4ac
Δ = 642-4·(-10)·100
Δ = 8096
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:

$\sqrt{\Delta}=\sqrt{8096}=\sqrt{16*506}=\sqrt{16}*\sqrt{506}=4\sqrt{506}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(64)-4\sqrt{506}}{2*-10}=\frac{-64-4\sqrt{506}}{-20}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(64)+4\sqrt{506}}{2*-10}=\frac{-64+4\sqrt{506}}{-20}
$