Question

If x=√5+2, then the value of x-1/x is

Answer 1

Answer:

4

Step-by-step explanation:

$\sqrt{5} + 2 - \frac{1}{ \sqrt{5} + 2 } = \frac{( { \sqrt{5} + 2)}^{2} - 1 }{ \sqrt{5} + 2} \\ = \frac{4 + 5 + 4 \sqrt{5} - 1 }{ \sqrt{5} + 2} \\ = \frac{8 + 4 \sqrt{5} }{2 + \sqrt{5} } \\ = \frac{4(2 + \sqrt{5}) }{2 + \sqrt{5} } \\ = 4$

Answer 2

Step-by-step explanation:

x=√5+2. [given]

x-1/x=. √5+2-1/√5+2

√5+2 and √5+2 are divided.

So, -1 is the correct answer.