已知x²-3x+1=0,求x³+1⼀x³的值

已知x²-3x+1=0,求x³+1/x³的值
2025-03-04 20:05:40
推荐回答(1个)
回答1:

x²-3x+1=0
→x-3+1/x=0
→x+1/x=3
→x³+1/x³=(x+1/x)^3-3[x^2(1/x)+x(1/x)^2]
=3^3-3(x+1/x)
=27-3*3=18