(20x-1)(x-20)=0

Solution for (20x-1)(x-20)=0 equation:

(20x-1)(x-20)=0

We multiply parentheses ..

(+20x^2-400x-1x+20)=0

We get rid of parentheses

20x^2-400x-1x+20=0

We add all the numbers together, and all the variables

20x^2-401x+20=0

a = 20; b = -401; c = +20;
Δ = b2-4ac
Δ = -4012-4·20·20
Δ = 159201
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{159201}=399$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-401)-399}{2*20}=\frac{2}{40}
=1/20
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-401)+399}{2*20}=\frac{800}{40}
=20
$