if x=1\5-x find x³+1\x³
plz answer asap
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x = 1/( 5 - x )
x (5 - x ) = 1
5x - x ² = 1
5x = 1 + x²
divide both sides by x
5 = 1/x + x
(x + 1/x ) = 5
so,
x³ + 1/x³ = (x +1/x )³ -3(x +1/x )
= (5)³ -3 (5)
= 125 -15
=110
x (5 - x ) = 1
5x - x ² = 1
5x = 1 + x²
divide both sides by x
5 = 1/x + x
(x + 1/x ) = 5
so,
x³ + 1/x³ = (x +1/x )³ -3(x +1/x )
= (5)³ -3 (5)
= 125 -15
=110
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