0=5-0.15x+0.001x^2

Solution for 0=5-0.15x+0.001x^2 equation:

0=5-0.15x+0.001x^2

We move all terms to the left:

0-(5-0.15x+0.001x^2)=0

We add all the numbers together, and all the variables

-(5-0.15x+0.001x^2)=0

We get rid of parentheses

-0.001x^2+0.15x-5=0

a = -0.001; b = 0.15; c = -5;
Δ = b2-4ac
Δ = 0.152-4·(-0.001)·(-5)
Δ = 0.0025
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{-(0.15)-\sqrt{0.0025}}{2*-0.001}=\frac{-0.15-\sqrt{0.0025}}{-0.002}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.15)+\sqrt{0.0025}}{2*-0.001}=\frac{-0.15+\sqrt{0.0025}}{-0.002}
$