81x2=64

Solution for 81x2=64 equation:

81x^2=64

We move all terms to the left:

81x^2-(64)=0

a = 81; b = 0; c = -64;
Δ = b2-4ac
Δ = 02-4·81·(-64)
Δ = 20736
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{20736}=144$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-144}{2*81}=\frac{-144}{162}
=-8/9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+144}{2*81}=\frac{144}{162}
=8/9
$