0.008-0.050x-3.95x^2=0

Solution for 0.008-0.050x-3.95x^2=0 equation:

0.008-0.050x-3.95x^2=0

We add all the numbers together, and all the variables

-3.95x^2-0.05x+0.008=0

a = -3.95; b = -0.05; c = +0.008;
Δ = b2-4ac
Δ = -0.052-4·(-3.95)·0.008
Δ = 0.1289
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{-(-0.05)-\sqrt{0.1289}}{2*-3.95}=\frac{0.05-\sqrt{0.1289}}{-7.9}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.05)+\sqrt{0.1289}}{2*-3.95}=\frac{0.05+\sqrt{0.1289}}{-7.9}
$