已知x²-5x+1=0(x≠0)求x²+x²/1的值.
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已知x²-5x+1=0(x≠0)求x²+x²/1的值.
已知x²-5x+1=0(x≠0)求x²+x²/1的值.
已知x²-5x+1=0(x≠0)求x²+x²/1的值.
x²-5x+1=0(x≠0)
除以x得 x-5+1/x=0
x+1/x=5
x²+1/x²
=x²+2+1/x²-2
=(x+1/x)²-2
=5²-2
=23
知x²-5x+1=0(x≠0)
两边除以x 得
x-5+1/x = 0
x+1/x = 5
平方得 x²+1/x² +2 =25
x²+x²/1 = 25-2 = 23