在多项式ax^5+bx^3+cx-7,当x=2时,值为5,那么x=-2,它的值为?

把x=2代入,得：32a+8b+2c-7=5,则：32a+8b+2c=12
x=-2时,ax^5+bx^3+cx-7=-32a-8b-2c-7
=-(32a+8b+2c)-7 把32a+8b+2c=12代入
=-12-7
=-19
所以,x=-2时,它的值为-19