x(x-20)2=50

Solution for x(x-20)2=50 equation:

x(x-20)2=50

We move all terms to the left:

x(x-20)2-(50)=0

We multiply parentheses

2x^2-40x-50=0

a = 2; b = -40; c = -50;
Δ = b2-4ac
Δ = -402-4·2·(-50)
Δ = 2000
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:

$\sqrt{\Delta}=\sqrt{2000}=\sqrt{400*5}=\sqrt{400}*\sqrt{5}=20\sqrt{5}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-40)-20\sqrt{5}}{2*2}=\frac{40-20\sqrt{5}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-40)+20\sqrt{5}}{2*2}=\frac{40+20\sqrt{5}}{4}
$