Need help ASAP please Thanks! (Algebra)

Question

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600

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Hello,

X + 1/X = 3 , then X^2 + 1/X^2 =.........

I tried solving it million times but yet i didn't find the correct answer..

It is 7 but i don't know the proof or how the model answer got it.

I got 9 by:

Square both sides

X^2 + 1/X^2=9 = X^2 + 1/X^2 = 9 as well?

Guest May 2, 2019

CPhill · Answer 1 · 2019-05-02T05:33:43

x + 1/x = 3 square both sdes

(x + 1/x)^2 = 3^2 simplify

x^2 + (x)(1/x) + (x)(1/x) + (1/x)^2 = 9

x^2 + 1 + 1 + (1/x^2) = 9

x^2 + 2 + (1/x)^2 = 9 subtract 2 from both sides

x^2 + (1/x)^2 = 7 ....and there you go !!!