x+x2=4,8

Solution for x+x2=4,8 equation:

x+x2=4.8

We move all terms to the left:

x+x2-(4.8)=0

We add all the numbers together, and all the variables

x^2+x-4.8=0

a = 1; b = 1; c = -4.8;
Δ = b2-4ac
Δ = 12-4·1·(-4.8)
Δ = 20.2
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{-(1)-\sqrt{20.2}}{2*1}=\frac{-1-\sqrt{20.2}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+\sqrt{20.2}}{2*1}=\frac{-1+\sqrt{20.2}}{2}
$