0=-x^2+115x+25

Solution for 0=-x^2+115x+25 equation:

0=-x^2+115x+25

We move all terms to the left:

0-(-x^2+115x+25)=0

We add all the numbers together, and all the variables

-(-x^2+115x+25)=0

We get rid of parentheses

x^2-115x-25=0

a = 1; b = -115; c = -25;
Δ = b2-4ac
Δ = -1152-4·1·(-25)
Δ = 13325
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:

$\sqrt{\Delta}=\sqrt{13325}=\sqrt{25*533}=\sqrt{25}*\sqrt{533}=5\sqrt{533}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-115)-5\sqrt{533}}{2*1}=\frac{115-5\sqrt{533}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-115)+5\sqrt{533}}{2*1}=\frac{115+5\sqrt{533}}{2}
$