if x-1/x=7,find x31/x3
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HEY!!
We know that ( a - b )3 = a3 + b3 - 3ab(a - b)
( x - 1)3 = x3 +1 - 3.x.1 (x - 1)
divide with x3
(x -1/x)3 =( x3 + 1)/x3 - 3x.7x/x3..........x-1=7x from problem
(7)3 = (x3 + 1)/x3 -21/x
343 + 21/x = x3 + 1/x3
We know that ( a - b )3 = a3 + b3 - 3ab(a - b)
( x - 1)3 = x3 +1 - 3.x.1 (x - 1)
divide with x3
(x -1/x)3 =( x3 + 1)/x3 - 3x.7x/x3..........x-1=7x from problem
(7)3 = (x3 + 1)/x3 -21/x
343 + 21/x = x3 + 1/x3
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hy
here is your answer
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here is your answer
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i already give this answer so see in picture i hope you got it
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