Question

若M的平方 +M-1=0,求M的立方+2M的平方+2007的值

Answer 1

M^2+M-1=0 所以M^2=1-M

M^2=1-M

M^3=M-M^2

原式=M-M^2+2M^2+2007

=M+M^2+2007

=M+1-M+2007

=2008