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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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