(x-10)(3x+6)=0

Solution for (x-10)(3x+6)=0 equation:

(x-10)(3x+6)=0

We multiply parentheses ..

(+3x^2+6x-30x-60)=0

We get rid of parentheses

3x^2+6x-30x-60=0

We add all the numbers together, and all the variables

3x^2-24x-60=0

a = 3; b = -24; c = -60;
Δ = b2-4ac
Δ = -242-4·3·(-60)
Δ = 1296
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1296}=36$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-24)-36}{2*3}=\frac{-12}{6}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-24)+36}{2*3}=\frac{60}{6}
=10
$