用余数定理好 (2x^4-3x^3+ax^2+7x+b)=(x+2)(x-1)A=(x^2+x-2)(2x^2-5x-3) 所以a = -3-4-5=-12 b=6 a/b=-2
2x^4-3x^3+ax^2+7x+b=(2x^2+mx+n)(x^2+x-2) =2x^4+(m+2)x^3+(-4+m+n)x^2+(-2m+n)x-2n m+2=-3 -4+m+n=a -2m+n=7 -2n=b m+2=-3 -2m+n=7 m=-5,n=-3 a=-4+m+n=-12 b=-2n=6 a/b=-2