[tex]D:x^2-2x-8\not=0\\
D:x^2-4x+2x-8\not=0\\
D:x(x-4)+2(x-4)\not=0\\
D:(x+2)(x-4)\not=0\\
D:x\not =-2 \wedge x\not =4\\\\
\frac{3x^2-18x+24}{x^2-2x-8}=0\\
\frac{3(x^2-6x+8)}{(x+2)(x-4)}=0\\
\frac{3(x^2-4x-2x+8)}{(x+2)(x-4)}=0\\
\frac{3(x(x-4)-2(x-4))}{(x+2)(x-4)}=0\\
\frac{3(x-2)(x-4)}{(x+2)(x-4)}=0\\
\frac{3(x-2)(x-4)}{(x+2)(x-4)}=0\\
\frac{3(x-2)}{(x+2)}=0|\cdot(x+2)\\
3(x-2)=0|:3\\
x-2=0\\
\boxed{x=2}
[/tex]
