((0.0007*(x^2))+(0.8*x))=50

Solution for ((0.0007*(x^2))+(0.8*x))=50 equation:

((0.0007(x^2))+(0.8x))=50

We move all terms to the left:

((0.0007(x^2))+(0.8x))-(50)=0

We add all the numbers together, and all the variables

((0.0007x^2)+(+0.8x))-50=0


We calculate terms in parentheses: +((0.0007x^2)+(+0.8x)), so:

(0.0007x^2)+(+0.8x)

We get rid of parentheses

0.0007x^2+0.8x

Back to the equation:

+(0.0007x^2+0.8x)


We get rid of parentheses

0.0007x^2+0.8x-50=0

a = 0.0007; b = 0.8; c = -50;
Δ = b2-4ac
Δ = 0.82-4·0.0007·(-50)
Δ = 0.78
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{-(0.8)-\sqrt{0.78}}{2*0.0007}=\frac{-0.8-\sqrt{0.78}}{0.0014}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.8)+\sqrt{0.78}}{2*0.0007}=\frac{-0.8+\sqrt{0.78}}{0.0014}
$