factor
group them
(x^3-3x^2)+(2x-6)>0
factor
(x^2)(x-3)+(2)(x-3)>0
we see a common factor of (x-3) so undistribute that
(x-3)(x^2+2)>0
set each greater than zero
x-3>0
x>3
x^2+2>0
x^2>-2
true for all real numbers because the square of any real number is always 0 or positive
the answer is all real numbers will work