4x^2-24x-405=0

Solution for 4x^2-24x-405=0 equation:

4x^2-24x-405=0

a = 4; b = -24; c = -405;
Δ = b2-4ac
Δ = -242-4·4·(-405)
Δ = 7056
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{7056}=84$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-24)-84}{2*4}=\frac{-60}{8}
=-7+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-24)+84}{2*4}=\frac{108}{8}
=13+1/2
$