问题
选择题
如果3x3-x=1,那么9x4+12x3-3x2-7x+2001的值等于( )
A.1999
B.2001
C.2003
D.2005
答案
∵3x3-x=1,
∴9x4+12x3-3x2-7x+2001,
=3x(3x3-x-1)+4(3x3-x-1)+2005,
=2005.
故选D.
如果3x3-x=1,那么9x4+12x3-3x2-7x+2001的值等于( )
A.1999
B.2001
C.2003
D.2005
∵3x3-x=1,
∴9x4+12x3-3x2-7x+2001,
=3x(3x3-x-1)+4(3x3-x-1)+2005,
=2005.
故选D.