If `x+1/x=9.` find the value of `x^4+1/(x^4)dot`

Explanation

Given:

`=> x+ 1/x=9`

Squaring both side, we get

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

`=> x^2+(1/x)^2+2x xx1/x=81`

`=> x^2+(1/x)^2+2=81`

`=> x^2+(1/x)^2=81-2`

`=> x^2+1/x^2=79.....................................(1)`

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