81x^2-800=0

Solution for 81x^2-800=0 equation:

81x^2-800=0

a = 81; b = 0; c = -800;
Δ = b2-4ac
Δ = 02-4·81·(-800)
Δ = 259200
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:

$\sqrt{\Delta}=\sqrt{259200}=\sqrt{129600*2}=\sqrt{129600}*\sqrt{2}=360\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-360\sqrt{2}}{2*81}=\frac{0-360\sqrt{2}}{162}
=-\frac{360\sqrt{2}}{162}
=-\frac{20\sqrt{2}}{9}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+360\sqrt{2}}{2*81}=\frac{0+360\sqrt{2}}{162}
=\frac{360\sqrt{2}}{162}
=\frac{20\sqrt{2}}{9}
$