-x^2+26*x-25=0

Solution for -x^2+26*x-25=0 equation:

-x^2+26x-25=0

We add all the numbers together, and all the variables

-1x^2+26x-25=0

a = -1; b = 26; c = -25;
Δ = b2-4ac
Δ = 262-4·(-1)·(-25)
Δ = 576
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{576}=24$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(26)-24}{2*-1}=\frac{-50}{-2}
=+25
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(26)+24}{2*-1}=\frac{-2}{-2}
=1
$