X2+0.2x=26

Solution for X2+0.2x=26 equation:

X2+0.2X=26

We move all terms to the left:

X2+0.2X-(26)=0

We add all the numbers together, and all the variables

X^2+0.2X-26=0

a = 1; b = 0.2; c = -26;
Δ = b2-4ac
Δ = 0.22-4·1·(-26)
Δ = 104.04
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{-(0.2)-\sqrt{104.04}}{2*1}=\frac{-0.2-\sqrt{104.04}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.2)+\sqrt{104.04}}{2*1}=\frac{-0.2+\sqrt{104.04}}{2}
$