10=70+-0,1x+-0,001x2

Solution for 10=70+-0,1x+-0,001x2 equation:

10=70+-0.1x+-0.001x^2

We move all terms to the left:

10-(70+-0.1x+-0.001x^2)=0

We use the square of the difference formula

-(70-0.1x-0.001x^2)+10=0

We get rid of parentheses

0.001x^2+0.1x-70+10=0

We add all the numbers together, and all the variables

0.001x^2+0.1x-60=0

a = 0.001; b = 0.1; c = -60;
Δ = b2-4ac
Δ = 0.12-4·0.001·(-60)
Δ = 0.25
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{-(0.1)-\sqrt{0.25}}{2*0.001}=\frac{-0.1-\sqrt{0.25}}{0.002}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.1)+\sqrt{0.25}}{2*0.001}=\frac{-0.1+\sqrt{0.25}}{0.002}
$