(6x+2)(5x-10)=0

Solution for (6x+2)(5x-10)=0 equation:

(6x+2)(5x-10)=0

We multiply parentheses ..

(+30x^2-60x+10x-20)=0

We get rid of parentheses

30x^2-60x+10x-20=0

We add all the numbers together, and all the variables

30x^2-50x-20=0

a = 30; b = -50; c = -20;
Δ = b2-4ac
Δ = -502-4·30·(-20)
Δ = 4900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4900}=70$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-50)-70}{2*30}=\frac{-20}{60}
=-1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-50)+70}{2*30}=\frac{120}{60}
=2
$