(8x-2)(5x+25)=0

Solution for (8x-2)(5x+25)=0 equation:

(8x-2)(5x+25)=0

We multiply parentheses ..

(+40x^2+200x-10x-50)=0

We get rid of parentheses

40x^2+200x-10x-50=0

We add all the numbers together, and all the variables

40x^2+190x-50=0

a = 40; b = 190; c = -50;
Δ = b2-4ac
Δ = 1902-4·40·(-50)
Δ = 44100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{44100}=210$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(190)-210}{2*40}=\frac{-400}{80}
=-5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(190)+210}{2*40}=\frac{20}{80}
=1/4
$