8.4^2+2.3^2=x^2

Solution for 8.4^2+2.3^2=x^2 equation:

8.4^2+2.3^2=x^2

We move all terms to the left:

8.4^2+2.3^2-(x^2)=0

We add all the numbers together, and all the variables

-1x^2+75.85=0

a = -1; b = 0; c = +75.85;
Δ = b2-4ac
Δ = 02-4·(-1)·75.85
Δ = 303.4
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{303.4}}{2*-1}=\frac{0-\sqrt{303.4}}{-2}
=-\frac{\sqrt{}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{303.4}}{2*-1}=\frac{0+\sqrt{303.4}}{-2}
=\frac{\sqrt{}}{-2}
$