X^2=20x+300

Solution for X^2=20x+300 equation:

X^2=20X+300

We move all terms to the left:

X^2-(20X+300)=0

We get rid of parentheses

X^2-20X-300=0

a = 1; b = -20; c = -300;
Δ = b2-4ac
Δ = -202-4·1·(-300)
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-40}{2*1}=\frac{-20}{2}
=-10
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+40}{2*1}=\frac{60}{2}
=30
$