x^2+(a-6)x+9-3a>0
x^2-6x+9+ax-3a>0
(x-3)^2+a(x-3)>0
(x-3)(x-3+a)>0
|a|≤1
-1≤a≤1
x-4≤x-3+a≤x-2
（x-3)(x-2)>0
x>3或x0
x>4或x4或x4或x