64c^2=81

Solution for 64c^2=81 equation:

64c^2=81

We move all terms to the left:

64c^2-(81)=0

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

$\sqrt{\Delta}=\sqrt{20736}=144$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-144}{2*64}=\frac{-144}{128}
=-1+1/8
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+144}{2*64}=\frac{144}{128}
=1+1/8
$