Question

x的平方+x-1,求1998x的3次方+3996x的平方是多少?

Answer 1

x^2+x-1=0 1998x^3+3996x^2=1998(x^3+x^2-x+x^2+x-1+1)=1998[x(x^2+x-1)+(x^2+x-1)+1]=1998