0=10+2x-0.05x^2

Solution for 0=10+2x-0.05x^2 equation:

0=10+2x-0.05x^2

We move all terms to the left:

0-(10+2x-0.05x^2)=0

We add all the numbers together, and all the variables

-(10+2x-0.05x^2)=0

We get rid of parentheses

0.05x^2-2x-10=0

a = 0.05; b = -2; c = -10;
Δ = b2-4ac
Δ = -22-4·0.05·(-10)
Δ = 6
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{-(-2)-\sqrt{6}}{2*0.05}=\frac{2-\sqrt{6}}{0.1}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+\sqrt{6}}{2*0.05}=\frac{2+\sqrt{6}}{0.1}
$