2x(3x-6)=210

Solution for 2x(3x-6)=210 equation:

2x(3x-6)=210

We move all terms to the left:

2x(3x-6)-(210)=0

We multiply parentheses

6x^2-12x-210=0

a = 6; b = -12; c = -210;
Δ = b2-4ac
Δ = -122-4·6·(-210)
Δ = 5184
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5184}=72$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-72}{2*6}=\frac{-60}{12}
=-5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+72}{2*6}=\frac{84}{12}
=7
$