(8+2x)(30-6x)=0

Solution for (8+2x)(30-6x)=0 equation:

(8+2x)(30-6x)=0

We add all the numbers together, and all the variables

(2x+8)(-6x+30)=0

We multiply parentheses ..

(-12x^2+60x-48x+240)=0

We get rid of parentheses

-12x^2+60x-48x+240=0

We add all the numbers together, and all the variables

-12x^2+12x+240=0

a = -12; b = 12; c = +240;
Δ = b2-4ac
Δ = 122-4·(-12)·240
Δ = 11664
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{11664}=108$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-108}{2*-12}=\frac{-120}{-24}
=+5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+108}{2*-12}=\frac{96}{-24}
=-4
$