0=x^2-20x+25

Solution for 0=x^2-20x+25 equation:

0=x^2-20x+25

We move all terms to the left:

0-(x^2-20x+25)=0

We add all the numbers together, and all the variables

-(x^2-20x+25)=0

We get rid of parentheses

-x^2+20x-25=0

We add all the numbers together, and all the variables

-1x^2+20x-25=0

a = -1; b = 20; c = -25;
Δ = b2-4ac
Δ = 202-4·(-1)·(-25)
Δ = 300
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:

$\sqrt{\Delta}=\sqrt{300}=\sqrt{100*3}=\sqrt{100}*\sqrt{3}=10\sqrt{3}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-10\sqrt{3}}{2*-1}=\frac{-20-10\sqrt{3}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+10\sqrt{3}}{2*-1}=\frac{-20+10\sqrt{3}}{-2}
$