已知㎡-5m-1=0 求2㎡-5m+1⼀㎡的值

2025-05-13 12:36:30
推荐回答(1个)
回答1:

m²-5m-1=0
m²-5m=1
两边除以m
m-5-1/m=0
m-1/m=5
2m²-5m+1/m²
=m²-5m+m²+1/m²
=1+(m-1/m)²+2
=3+25
=28