0=-15x^2+1350x-12000

Solution for 0=-15x^2+1350x-12000 equation:

0=-15x^2+1350x-12000

We move all terms to the left:

0-(-15x^2+1350x-12000)=0

We add all the numbers together, and all the variables

-(-15x^2+1350x-12000)=0

We get rid of parentheses

15x^2-1350x+12000=0

a = 15; b = -1350; c = +12000;
Δ = b2-4ac
Δ = -13502-4·15·12000
Δ = 1102500
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1102500}=1050$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1350)-1050}{2*15}=\frac{300}{30}
=10
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1350)+1050}{2*15}=\frac{2400}{30}
=80
$