-127.5=-0.005x^2-0.1x

Solution for -127.5=-0.005x^2-0.1x equation:

-127.5=-0.005x^2-0.1x

We move all terms to the left:

-127.5-(-0.005x^2-0.1x)=0

We get rid of parentheses

0.005x^2+0.1x-127.5=0

a = 0.005; b = 0.1; c = -127.5;
Δ = b2-4ac
Δ = 0.12-4·0.005·(-127.5)
Δ = 2.56
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{2.56}}{2*0.005}=\frac{-0.1-\sqrt{2.56}}{0.01}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.1)+\sqrt{2.56}}{2*0.005}=\frac{-0.1+\sqrt{2.56}}{0.01}
$