x^2 -3x-3>0
x²-3x+(3/2)²-3-9/4＞0
(x-3/2)²-21/4＞0
[(x-3/2)+(√21)/2][(x-3/2)-(√21)/2]＞0
[x-(3-√21)/2][x-(3+√21)/2]＞0
∴x＞(3+√21)/2或x＜(3-√21)/2