0=2500-400x+12x^2

Solution for 0=2500-400x+12x^2 equation:

0=2500-400x+12x^2

We move all terms to the left:

0-(2500-400x+12x^2)=0

We add all the numbers together, and all the variables

-(2500-400x+12x^2)=0

We get rid of parentheses

-12x^2+400x-2500=0

a = -12; b = 400; c = -2500;
Δ = b2-4ac
Δ = 4002-4·(-12)·(-2500)
Δ = 40000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{40000}=200$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(400)-200}{2*-12}=\frac{-600}{-24}
=+25
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(400)+200}{2*-12}=\frac{-200}{-24}
=8+1/3
$