Question

12. If x + 1/x = 7 , find the value of
a) x² + 1/x²
b) x³ + 1/x³
c) x^4 +1/x^4

Answer 1

Answer:

$\huge\mathkal\red{Given Equation is x² + (1/x²) = 7.It can be written as,⇒ x² + (1/x²) = 9 - 2⇒ x² + (1/x²) + 2 = 9⇒ (x + 1/x)² = 9⇒ x + 1/x = 3.On cubing both sides, we get⇒ (x + 1/x)³ = (3)³⇒ x³ + 1/x³ + 3(x + 1/x) = 27⇒ x³ + 1/x³ + 3(3) = 27⇒ x³ + 1/x³ + 9 = 27⇒ x³ + 1/x³ = 18.Hope it helps!}$

Step-by-step explanation: