3=-0.005x^2+0.17x+3

Solution for 3=-0.005x^2+0.17x+3 equation:

3=-0.005x^2+0.17x+3

We move all terms to the left:

3-(-0.005x^2+0.17x+3)=0

We get rid of parentheses

0.005x^2-0.17x-3+3=0

We add all the numbers together, and all the variables

0.005x^2-0.17x=0

a = 0.005; b = -0.17; c = 0;
Δ = b2-4ac
Δ = -0.172-4·0.005·0
Δ = 0.0289
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{-(-0.17)-\sqrt{0.0289}}{2*0.005}=\frac{0.17-\sqrt{0.0289}}{0.01}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.17)+\sqrt{0.0289}}{2*0.005}=\frac{0.17+\sqrt{0.0289}}{0.01}
$