36=8*a2

Solution for 36=8*a2 equation:

36=8a^2

We move all terms to the left:

36-(8a^2)=0

a = -8; b = 0; c = +36;
Δ = b2-4ac
Δ = 02-4·(-8)·36
Δ = 1152
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1152}=\sqrt{576*2}=\sqrt{576}*\sqrt{2}=24\sqrt{2}$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-24\sqrt{2}}{2*-8}=\frac{0-24\sqrt{2}}{-16}
=-\frac{24\sqrt{2}}{-16}
=-\frac{3\sqrt{2}}{-2}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+24\sqrt{2}}{2*-8}=\frac{0+24\sqrt{2}}{-16}
=\frac{24\sqrt{2}}{-16}
=\frac{3\sqrt{2}}{-2}
$