∴2x4-3x3+ax2+7x+b能被(x+2)(x-1)整除,
設商是A.
則2x4-3x3+ax2+7x+b=A(x+2)(x-1),
則x=-2和x=1時,右邊都等于0,所以左邊也等于0.
當x=-2時,2x4-3x3+ax2+7x+b=32+24+4a-14+b=4a+b+42=0 ①
當x=1時,2x4-3x3+ax2+7x+b=2-3+a+7+b=a+b+6=0 ②
①-②,得
3a+36=0,
∴a=-12,
∴b=-6-a=6.
∴
a |
b |
?12 |
6 |
故答案為-2.
a |
b |
a |
b |
?12 |
6 |