Question

Solve this question given in photo.

Answer 1

Answer:

0

Step-by-step explanation:

Given: (x - 1/x) = 3

(i)

On cubing both sides, we get

⇒ (x - 1/x)³ = (3)³

⇒ x³ - (1/x³) - 3(x)(1/x)(x - 1/x) = 27

⇒ x³ - (1/x³) - 3(3) = 27

⇒ x³ - (1/x³) = 27 + 9

⇒ x³ - (1/x³) = 36

(ii)

On squaring the equation both sides, we get

(x - 1/x)² = (3)²

⇒ x² + 1/x² - 2 = 9

⇒ x² + 1/x² = 11

Now,

Given: 2(x³ - 1/x³) - 3(x² + 1/x²) - 39

⇒ 2(36) - 3(11) - 39

⇒ 72 - 72

⇒ 0

Hope it helps!

Answer 2

Answer:

0

Step-by-step explanation:

(x - 1/x) = 3

Square both sides,

(x - 1/x)^2 = 3^2

x^2 + 1/x^2 - 2 = 9

x^2 + 1/x^2 = 11

Cubing both sides,

x^3 - 1/x^3 - 3(x - 1/x) = 27

x^3 - 1/x^3 - 3(3) = 27

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

x^3 - 1/x^3 = 36

Substitute in given equation.

2(x^3 - 1/x^3) - 3(x^2 + 1/x^2) - 39

2(36) - 3(11) - 39

72 - 72

0

Hope it helps you.