100x2=81

Solution for 100x2=81 equation:

100x^2=81

We move all terms to the left:

100x^2-(81)=0

a = 100; b = 0; c = -81;
Δ = b2-4ac
Δ = 02-4·100·(-81)
Δ = 32400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{32400}=180$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-180}{2*100}=\frac{-180}{200}
=-9/10
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+180}{2*100}=\frac{180}{200}
=9/10
$