(5x-20)(2x+24)=0

Solution for (5x-20)(2x+24)=0 equation:

(5x-20)(2x+24)=0

We multiply parentheses ..

(+10x^2+120x-40x-480)=0

We get rid of parentheses

10x^2+120x-40x-480=0

We add all the numbers together, and all the variables

10x^2+80x-480=0

a = 10; b = 80; c = -480;
Δ = b2-4ac
Δ = 802-4·10·(-480)
Δ = 25600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{25600}=160$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(80)-160}{2*10}=\frac{-240}{20}
=-12
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(80)+160}{2*10}=\frac{80}{20}
=4
$