x2-4.86x-20.8=3.29

Solution for x2-4.86x-20.8=3.29 equation:

x2-4.86x-20.8=3.29

We move all terms to the left:

x2-4.86x-20.8-(3.29)=0

We add all the numbers together, and all the variables

x^2-4.86x-24.09=0

a = 1; b = -4.86; c = -24.09;
Δ = b2-4ac
Δ = -4.862-4·1·(-24.09)
Δ = 119.9796
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{-(-4.86)-\sqrt{119.9796}}{2*1}=\frac{4.86-\sqrt{119.9796}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4.86)+\sqrt{119.9796}}{2*1}=\frac{4.86+\sqrt{119.9796}}{2}
$