已知X=1时,ax3+bx2+cx+3=0,则X=-1时,aX3-bx2+cx+3的值为多少
问题描述:
已知X=1时,ax3+bx2+cx+3=0,则X=-1时,aX3-bx2+cx+3的值为多少
答
x=1
ax³+bx²+cx+3
=a+b+c+3=0
a+b+c=-3
x=-1
ax³-bx²+cx+3
=-a-b-c+3
=-(a+b+c)+3
=-(-3)+3
=6