Question

Guys plz don't spam and answer this fast ​

Answer 1

Step-by-step explanation: x³  - x⁻³ = ± 756  if x⁴ – 83x² +1 = 0 (option b is correct)

x⁴ – 83x² +1 = 0

Dividing both sides by x²

=> x² - 83 + 1/x² = 0

=>  x² + 1/x²  = 83

=> (x - 1/x)² + 2x(1/x) = 83

=>  (x - 1/x)² + 2 = 83

=> (x - 1/x)²  = 81

=> x - 1/x  =  ±9

Cubing both sides

=> (x - 1/x)³  = (±9)³

=> x³  - 1/x³  - 3x(1/x)(x - 1/x) = ±729

=>  x³  - 1/x³  - 3(±9)  = ±729

=> x³  - 1/x³ = ±729 ± 27

=> x³  - 1/x³ = ± 756

=> x³  - x⁻³ = ± 756