问题
选择题
当x=3时,代数式px3+qx+3的值是2008,则当x=-3时,代数式px3+qx+3的值为( )
A.-2002
B.2002
C.-2003
D.2003
答案
当x=3时,px3+qx+3=27p+3q+3=2008,
∴27p+3q=2005,
∴当x=-3时,px3+qx+3=-27p-3q+3=-(27p+3q)+3=-2005+3=-2002.
故选A.
当x=3时,代数式px3+qx+3的值是2008,则当x=-3时,代数式px3+qx+3的值为( )
A.-2002
B.2002
C.-2003
D.2003
当x=3时,px3+qx+3=27p+3q+3=2008,
∴27p+3q=2005,
∴当x=-3时,px3+qx+3=-27p-3q+3=-(27p+3q)+3=-2005+3=-2002.
故选A.