x(x-280)=-4500

Solution for x(x-280)=-4500 equation:

x(x-280)=-4500

We move all terms to the left:

x(x-280)-(-4500)=0

We add all the numbers together, and all the variables

x(x-280)+4500=0

We multiply parentheses

x^2-280x+4500=0

a = 1; b = -280; c = +4500;
Δ = b2-4ac
Δ = -2802-4·1·4500
Δ = 60400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{60400}=\sqrt{400*151}=\sqrt{400}*\sqrt{151}=20\sqrt{151}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-280)-20\sqrt{151}}{2*1}=\frac{280-20\sqrt{151}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-280)+20\sqrt{151}}{2*1}=\frac{280+20\sqrt{151}}{2}
$