已知x²-4x+1=0(x≠0),求x³+1/x³
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已知x²-4x+1=0(x≠0),求x³+1/x³
已知x²-4x+1=0(x≠0),求x³+1/x³
已知x²-4x+1=0(x≠0),求x³+1/x³
等式两边同除以x
x- 4 +1/x=0
x+1/x=4
x³+1/x³=(x+1/x)(x²-1+1/x²)
=(x+1/x)[(x+1/x)² -3]
=4×(4²-3)
=52