26=81x^2

Solution for 26=81x^2 equation:

26=81x^2

We move all terms to the left:

26-(81x^2)=0

a = -81; b = 0; c = +26;
Δ = b2-4ac
Δ = 02-4·(-81)·26
Δ = 8424
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:

$\sqrt{\Delta}=\sqrt{8424}=\sqrt{324*26}=\sqrt{324}*\sqrt{26}=18\sqrt{26}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-18\sqrt{26}}{2*-81}=\frac{0-18\sqrt{26}}{-162}
=-\frac{18\sqrt{26}}{-162}
=-\frac{\sqrt{26}}{-9}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+18\sqrt{26}}{2*-81}=\frac{0+18\sqrt{26}}{-162}
=\frac{18\sqrt{26}}{-162}
=\frac{\sqrt{26}}{-9}
$