Question

If x+x-¹ = 11, evaluate x²+x-²

A. 119
B. 120
C. 121
D. 122

no spam answers please and kindly explain ur answer.​

Answer 1

THE CORRECT ANSWER IS A. 119

Given x+x-¹ = 11

now square both the side

(x+x-¹)² = 11²

now open the bracket of RHS and apply (a+b)²

you'll get,

x²+2x/x+ 1/x² =121

simplify above equation you'll get,

x²+ 2 + x-² = 121

shift the equation,

x² + x-² = 121 - 2

x² + x-² = 119 !