0=-0.002x^2+x+55

Solution for 0=-0.002x^2+x+55 equation:

0=-0.002x^2+x+55

We move all terms to the left:

0-(-0.002x^2+x+55)=0

We add all the numbers together, and all the variables

-(-0.002x^2+x+55)=0

We get rid of parentheses

0.002x^2-x-55=0

We add all the numbers together, and all the variables

0.002x^2-1x-55=0

a = 0.002; b = -1; c = -55;
Δ = b2-4ac
Δ = -12-4·0.002·(-55)
Δ = 1.44
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{1.44}}{2*0.002}=\frac{1-\sqrt{1.44}}{0.004}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+\sqrt{1.44}}{2*0.002}=\frac{1+\sqrt{1.44}}{0.004}
$