1500+20x-x^2=0

Solution for 1500+20x-x^2=0 equation:

1500+20x-x^2=0

We add all the numbers together, and all the variables

-1x^2+20x+1500=0

a = -1; b = 20; c = +1500;
Δ = b2-4ac
Δ = 202-4·(-1)·1500
Δ = 6400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6400}=80$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-80}{2*-1}=\frac{-100}{-2}
=+50
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+80}{2*-1}=\frac{60}{-2}
=-30
$