Question

pls answer this question​

Answer 1

Answer:

Step-by-step explanation:

Answers

We need to find

x^3 + 1/x^3

We are given,

x + 1/x = 3

We know that,

(a+b)^3 = a^3 + b^3 + 3ab(a+b) }

Lets take the cube of both sides of the given equation,

=> (x + 1/x)^3 = 3^3

=> x^3 + 1/x^3 + {3 . x . 1/x (x + 1/x)} = 27

=> x^3 + 1/x^3 + 3(x + 1/x) = 27

Since x + 1/x = 3

=> x^3 + 1/x^3 + 3×3 = 27

=> x^3 + 1/x^3 = 27-9

=> x^3 + 1/x^3 = 18

Hope it helps u

Answer 2

Answer:

hope it will help you

Step-by-step explanation:

x+1/x = 3

Cubing on both sides

(x+1/x)³ = 3³

x³+1/x³+3.x.1/x (x+x/1) = 27

x³+1/x³+3(3) = 27

x³+1/x³+9 = 27

x³+1/x³ = 27-9

x³+1/x³ = 18