1000=5500-5x^2

Solution for 1000=5500-5x^2 equation:

1000=5500-5x^2

We move all terms to the left:

1000-(5500-5x^2)=0

We get rid of parentheses

5x^2-5500+1000=0

We add all the numbers together, and all the variables

5x^2-4500=0

a = 5; b = 0; c = -4500;
Δ = b2-4ac
Δ = 02-4·5·(-4500)
Δ = 90000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{90000}=300$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-300}{2*5}=\frac{-300}{10}
=-30
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+300}{2*5}=\frac{300}{10}
=30
$