3(x^2-2x-24)=0

Solution for 3(x^2-2x-24)=0 equation:

3(x^2-2x-24)=0

We multiply parentheses

3x^2-6x-72=0

a = 3; b = -6; c = -72;
Δ = b2-4ac
Δ = -62-4·3·(-72)
Δ = 900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{900}=30$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-30}{2*3}=\frac{-24}{6}
=-4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+30}{2*3}=\frac{36}{6}
=6
$