100-2x^2=71.12

Solution for 100-2x^2=71.12 equation:

100-2x^2=71.12

We move all terms to the left:

100-2x^2-(71.12)=0

We add all the numbers together, and all the variables

-2x^2+28.88=0

a = -2; b = 0; c = +28.88;
Δ = b2-4ac
Δ = 02-4·(-2)·28.88
Δ = 231.04
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-\sqrt{231.04}}{2*-2}=\frac{0-\sqrt{231.04}}{-4}
=-\frac{\sqrt{}}{-4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{231.04}}{2*-2}=\frac{0+\sqrt{231.04}}{-4}
=\frac{\sqrt{}}{-4}
$