Question

已知m的平方-m-1=0,求代数式m的立方-2m+1的值 要解释清楚每一步的意思.

Answer 1

m的平方-m-1=0
则m²-m=1
m的立方-2m+1
=m³-m²+m²-2m+1
=m(m²-m)+m²-2m+1
=m×1+m²-2m+1
=m²-m+1
=1+1
=2