21.9-(x*x)=0

Solution for 21.9-(x*x)=0 equation:

21.9-(x*x)=0

We add all the numbers together, and all the variables

-(+x*x)+21.9=0

We get rid of parentheses

-x*x+21.9=0

Wy multiply elements

-1x^2+21.9=0

a = -1; b = 0; c = +21.9;
Δ = b2-4ac
Δ = 02-4·(-1)·21.9
Δ = 87.6
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{87.6}}{2*-1}=\frac{0-\sqrt{87.6}}{-2}
=-\frac{\sqrt{}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{87.6}}{2*-1}=\frac{0+\sqrt{87.6}}{-2}
=\frac{\sqrt{}}{-2}
$