4x^2-200=20

Solution for 4x^2-200=20 equation:

4x^2-200=20

We move all terms to the left:

4x^2-200-(20)=0

We add all the numbers together, and all the variables

4x^2-220=0

a = 4; b = 0; c = -220;
Δ = b2-4ac
Δ = 02-4·4·(-220)
Δ = 3520
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:

$\sqrt{\Delta}=\sqrt{3520}=\sqrt{64*55}=\sqrt{64}*\sqrt{55}=8\sqrt{55}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-8\sqrt{55}}{2*4}=\frac{0-8\sqrt{55}}{8}
=-\frac{8\sqrt{55}}{8}
=-\sqrt{55}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+8\sqrt{55}}{2*4}=\frac{0+8\sqrt{55}}{8}
=\frac{8\sqrt{55}}{8}
=\sqrt{55}
$