0.4^2+1^2=e^2

Solution for 0.4^2+1^2=e^2 equation:

0.4^2+1^2=e^2

We move all terms to the left:

0.4^2+1^2-(e^2)=0

We add all the numbers together, and all the variables

-1e^2+1.16=0

a = -1; b = 0; c = +1.16;
Δ = b2-4ac
Δ = 02-4·(-1)·1.16
Δ = 4.64
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$e_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$e_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$e_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-\sqrt{4.64}}{2*-1}=\frac{0-\sqrt{4.64}}{-2}
=-\frac{\sqrt{}}{-2}
$
$e_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{4.64}}{2*-1}=\frac{0+\sqrt{4.64}}{-2}
=\frac{\sqrt{}}{-2}
$