81x^2-81x+20=0

Solution for 81x^2-81x+20=0 equation:

81x^2-81x+20=0

a = 81; b = -81; c = +20;
Δ = b2-4ac
Δ = -812-4·81·20
Δ = 81
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{81}=9$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-81)-9}{2*81}=\frac{72}{162}
=4/9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-81)+9}{2*81}=\frac{90}{162}
=5/9
$