(20x+10)(x-6)=0

Solution for (20x+10)(x-6)=0 equation:

(20x+10)(x-6)=0

We multiply parentheses ..

(+20x^2-120x+10x-60)=0

We get rid of parentheses

20x^2-120x+10x-60=0

We add all the numbers together, and all the variables

20x^2-110x-60=0

a = 20; b = -110; c = -60;
Δ = b2-4ac
Δ = -1102-4·20·(-60)
Δ = 16900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{16900}=130$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-110)-130}{2*20}=\frac{-20}{40}
=-1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-110)+130}{2*20}=\frac{240}{40}
=6
$