3=0.005x^2+x+6

Solution for 3=0.005x^2+x+6 equation:

3=0.005x^2+x+6

We move all terms to the left:

3-(0.005x^2+x+6)=0

We get rid of parentheses

-0.005x^2-x-6+3=0

We add all the numbers together, and all the variables

-0.005x^2-1x-3=0

a = -0.005; b = -1; c = -3;
Δ = b2-4ac
Δ = -12-4·(-0.005)·(-3)
Δ = 0.94
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{0.94}}{2*-0.005}=\frac{1-\sqrt{0.94}}{-0.01}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+\sqrt{0.94}}{2*-0.005}=\frac{1+\sqrt{0.94}}{-0.01}
$