-4x^2+220=0

Solution for -4x^2+220=0 equation:

-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}
=-\frac{\sqrt{55}}{-1}
$
$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}
=\frac{\sqrt{55}}{-1}
$