若x=根号5+2,求x³-3x²-5x+2007的值.

x³-3x²-5x+2007
=(x³-3x²-4x)-x+2007
=x(x²-3x-4)-x+2007
=x(x-4)(x+1)-x+2007
=(√5+2)(√5+2-4)(√5+2+1)-(√5+2)+2007
=(√5+2)(√5-2)(√5+3)-√5-2+2007
=(5-4)(√5+3)-√5+2005
=√5+3-√5+2005
=2008