If x = (√2 + 1)−1/3, the value of x3

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x = (√2 + 1)^−1/3
⇒ x⁻³ = √2 + 1

⇒	1	= √2 + 1
	x³

and x³ =	1	=	1(√2 − 1)
	√2 + 1		(√2 + 1) (√2 − 1)

= √2 − 1

∴ x³ −	1
	x³

= √2 − 1 − √2 − 1 = – 2