0=75-130.375*x-0.25*x^2

Solution for 0=75-130.375*x-0.25*x^2 equation:

0=75-130.375x-0.25x^2

We move all terms to the left:

0-(75-130.375x-0.25x^2)=0

We add all the numbers together, and all the variables

-(75-130.375x-0.25x^2)=0

We get rid of parentheses

0.25x^2+130.375x-75=0

a = 0.25; b = 130.375; c = -75;
Δ = b2-4ac
Δ = 130.3752-4·0.25·(-75)
Δ = 17072.640625
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{-(130.375)-\sqrt{17072.640625}}{2*0.25}=\frac{-130.375-\sqrt{17072.640625}}{0.5}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(130.375)+\sqrt{17072.640625}}{2*0.25}=\frac{-130.375+\sqrt{17072.640625}}{0.5}
$