m^2-3m+1=0,求m+1/m的值,m^2+1/m^2

Question

m^2-3m+1=0,求m+1/m的值 ,m^2+1/m^2

Answer 1

m^2-3m+1=0
两边同时除以m
m-3+1/m=0
m+1/m=3
(m+1/m)²=9
m²+1/m²+2=9
m²+1/m²=7
不懂的欢迎追问.