300=36x-x^2

Solution for 300=36x-x^2 equation:

300=36x-x^2

We move all terms to the left:

300-(36x-x^2)=0

We get rid of parentheses

x^2-36x+300=0

a = 1; b = -36; c = +300;
Δ = b2-4ac
Δ = -362-4·1·300
Δ = 96
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:

$\sqrt{\Delta}=\sqrt{96}=\sqrt{16*6}=\sqrt{16}*\sqrt{6}=4\sqrt{6}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-36)-4\sqrt{6}}{2*1}=\frac{36-4\sqrt{6}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-36)+4\sqrt{6}}{2*1}=\frac{36+4\sqrt{6}}{2}
$