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If x + 1/x = 7, then what is the value of x^2 + 1/(x^2) + 1?

 

Thanks.

Guest Apr 4, 2018
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If x + 1/x = 7, then what is the value of x^2 + 1/(x^2) + 1?

 

Note that

 

(x + 1/x)^2   = 7^2

 

x^2  + 2 (x * 1/x)  + (1/x)^2  = 49

 

x^2  + 2(1)  + 1/x^2  =  49

 

x^2  +  2  +  1/x^2   =  49      subtract 2 from both sides

 

x^2  + 1/x^2   =  47   ......so.....

 

x^2 + 1/x^2  + 1   =  47  + 1

 

x^2 + 1/x^2 +  1   = 48

 

 

cool cool cool

CPhill  Apr 4, 2018

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