（1）当x=2时,代数式ax^5+bx^3+cx+3的值为27,则当x=-2时,求原代数式的值.（2）已知a+b/a-b=2,求a+b/2(a-b) - 3(a-b)/a+b的值

Question

（1）当x=2时,代数式ax^5+bx^3+cx+3的值为27,则当x=-2时,求原代数式的值.
（2）已知a+b/a-b=2,求a+b/2(a-b) - 3(a-b)/a+b的值

Answer 1

1.当x=2时,ax^5+bx^3+cx+3=27即32a+8b+2c=3=27,
32a+8b=24-2c,
当x=-2时,ax^5+bx^3+cx+3=-32a-8b-2c+3=-(32a+8b)-2c+3=-(24-2c)-2c+3=-24+2c-2c+3=-21
2.a+b/2(a-b) - 3(a-b)/a+b=1/2*(a+b/a-b)-3*(a+b/a-b)=2*1/2-3*2=-5.