4x2-20=880

Solution for 4x2-20=880 equation:

4x^2-20=880

We move all terms to the left:

4x^2-20-(880)=0

We add all the numbers together, and all the variables

4x^2-900=0

a = 4; b = 0; c = -900;
Δ = b2-4ac
Δ = 02-4·4·(-900)
Δ = 14400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{14400}=120$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-120}{2*4}=\frac{-120}{8}
=-15
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+120}{2*4}=\frac{120}{8}
=15
$