0,2x+0,006x2=50

Solution for 0,2x+0,006x2=50 equation:

0.2x+0.006x^2=50

We move all terms to the left:

0.2x+0.006x^2-(50)=0

a = 0.006; b = 0.2; c = -50;
Δ = b2-4ac
Δ = 0.22-4·0.006·(-50)
Δ = 1.24
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{1.24}}{2*0.006}=\frac{-0.2-\sqrt{1.24}}{0.012}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.2)+\sqrt{1.24}}{2*0.006}=\frac{-0.2+\sqrt{1.24}}{0.012}
$