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

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

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

We add all the numbers together, and all the variables

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

We multiply parentheses ..

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

We get rid of parentheses

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

We add all the numbers together, and all the variables

10x^2-10x-60=0

a = 10; b = -10; c = -60;
Δ = b2-4ac
Δ = -102-4·10·(-60)
Δ = 2500
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2500}=50$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-10)-50}{2*10}=\frac{-40}{20}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-10)+50}{2*10}=\frac{60}{20}
=3
$