If √x + 4 + √x − 4 = 2 then x

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√x + 4 + √x − 4	=	2
√x + 4 − √x − 4	=	1

By componendo and dividendo,

2√x + 4	=	3
2√x − 4	=	1

On squaring,

x + 4	=	9
x − 4	=	1

⇒ 9x – 36 = x + 4
⇒ 9x – x = 36 + 4
⇒ 8x = 40
⇒ x = 5

If	√x + 4 + √x − 4	= 2 then x is equal to
	√x + 4 − √x − 4