If x3 + y3 = 35 and x + y = 5, then the value of 1 + 1

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Using Rule 8
∴ (x + y)³ = x³ + y³ + 3 (xy)
(x + y)
⇒ 125 = 35 + 3(5) xy
⇒ 15xy = 125 – 35 = 90

⇒ xy =	90	= 6
	15

⇒	x + y	=	1	+	1
	xy		x		y

⇒	x + y	=	5
	xy		6

If x³ + y³ = 35 and x + y = 5, then the value of	1	+	1	will be :
	x		y