Question

已知M的平方+M=1=0那么代数式M的3次方+2M(M的平方)-1997的值

Answer 1

M²+M+1=0 还是 M²+M-1=0?

如果是M²+M-1=0则可

M³+M²-M=0,即M³+M²=M

则M³+2M²-1997

=(M³+M²)+M²-1997

=M²+M-1997

=1-1997

=-1996