Question

if x=5-√21/2

, find the value of x +1/x​

Answer 1

Answer:

hi how are you where do you live with

Answer 2

Step-by-step explanation:

Given, x = (5-√21)/2.

1/x = 2/(5-√21).

Rationalising 1/x, we get

1/x = 2/(5-√21)*[(5+√21)/(5+√21)]

1/x = 2*(5+√21)/[(5-√21)*(5+√21)]

1/x = 2*(5+√21)/[5² -(√21)²]

1/x = 2*(5+√21)/(25-21)

1/x = 2*(5+√21)/4

1/x = (5+√21)/2

x + 1/x = (5-√21)/2 + (5+√21)/2

= (5-√21 + 5+√21)/2

= 10/2 = 5.

Thus, x + 1/x = 5.