0=x2-20x+36

Solution for 0=x2-20x+36 equation:

0=x2-20x+36

We move all terms to the left:

0-(x2-20x+36)=0

We add all the numbers together, and all the variables

-(+x^2-20x+36)+0=0

We add all the numbers together, and all the variables

-(+x^2-20x+36)=0

We get rid of parentheses

-x^2+20x-36=0

We add all the numbers together, and all the variables

-1x^2+20x-36=0

a = -1; b = 20; c = -36;
Δ = b2-4ac
Δ = 202-4·(-1)·(-36)
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-16}{2*-1}=\frac{-36}{-2}
=+18
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+16}{2*-1}=\frac{-4}{-2}
=+2
$