If x = 999, y = 1000, z = 1001, then the value of x³

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If x = 999, y = 1000, z = 1001, then the value of
x³ + y³ + z³ - 3xyz is :
x - y + z

x³ + y³ + z³ – 3xyz = 1/2 (x + y + z) {(x – y)² + (y – z)² + (z – x)²}

∴	x³ + y³ + z³ – 3xyz
	x - y + z

=	1/2(x + y + z){(x-y)² + (y-z)² + (y-z)² + (z-x)²}
	x - y + z

=	1	(999 + 1000 + 100) =	{999 + 1000)² + (1000 - 10001)² + (1001 + 999)²}
	2		(999 - 1000 + 1001)

=	3000	× (1 + 1 + 4)
	2 × 1000

=	18	= 9
	2