1.

if ` x^4 + 1/ x^4 = 322` then find the value of `x^3 - 1/x^3`

Answer» `x^4+1/x^4=322`
`x^4+1/x^4+2-2=322`
`(x^2+1/x^2)^2=324`
`x^2+1/x^2=18`
`x^2+1/x^2-2=16`
`(x-1/x)^2=16`
`x-1/x=4-(2)`
`x^2+1/x^2=18-(1)`
`(x^3-1/x^3)=(x-1/x)(x^2+1/x^2+x*1/x)`
`=4*(18+1)=4*19=76`.


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