Question

x+1/x=3 then find the value of x^3+1/x^3​

Answer 1

hey mate!

Answer :

36

Step-by-step explanation :

x - 1 / x = 3

On cubing both sides ;

( x - 1 / x ) = ( 3 )³

Using Identity :

( a - b )³ = a³ - b³ - 3 ab ( a - b )

⇒ x³ - 1 / x³ - 3 ( x - 1 / x ) = 27

⇒ x³ - 1 / x³ - 3 ( 3 ) = 27

⇒ x³ - 1 / x³ - 9 = 27

⇒ x³ - 1 / x³ = 27 + 9

⇒ x³ - 1 / x³ = 36

hence the answer is 36

Answer 2

Answer:

x+1/x  =  3

x+1     =  3x

3x-x   = 1

2x      = 1

x        =1/2

so substituting the value x=1/2 in x³+1/x³, we get the answer as 9.

Step-by-step explanation: