Question

若多项式x3+(k+3)x2-x-4-2x2缺少x2项,求k2-1的值

Answer 1

x^3+(k+3)x^2-x-4-2x^2=x^3+(k+1)x^2-x-4

因为多项式缺少x^2项,所以k+1=0,即k^2-1=(k+1)(k-1)=0