0=-20x2+1400x+36000

Solution for 0=-20x2+1400x+36000 equation:

0=-20x^2+1400x+36000

We move all terms to the left:

0-(-20x^2+1400x+36000)=0

We add all the numbers together, and all the variables

-(-20x^2+1400x+36000)=0

We get rid of parentheses

20x^2-1400x-36000=0

a = 20; b = -1400; c = -36000;
Δ = b2-4ac
Δ = -14002-4·20·(-36000)
Δ = 4840000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4840000}=2200$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1400)-2200}{2*20}=\frac{-800}{40}
=-20
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1400)+2200}{2*20}=\frac{3600}{40}
=90
$