x+1/x=3 问X^2+1/X^2=?

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x+1/x=3问X^2+1/X^2=?x+1/x=3问X^2+1/X^2=?x+1/x=3问X^2+1/X^2=?x^2+1/(x^2)=(x+1/x)^2-2=3^2-2=9-2=7x+1/x=3所

x+1/x=3 问X^2+1/X^2=?
x+1/x=3 问X^2+1/X^2=?

x+1/x=3 问X^2+1/X^2=?
x^2+1/(x^2)=(x+1/x)^2-2=3^2-2=9-2=7

x+1/x=3
所以(x+1/x)^2=x^2+1/x^2+2=9
所以x^2+1/x^2=7

(X+1/x)^2=9讲这个等式两边张开就可以了那 结果等于7