Question

solve this Q, accurate answer please​

Answer 1

We have,

√(86.49) + √(5 + k²) = 12.3

⇒√(9.3)² + √(5 + k²) = 12.3

⇒ √(5 + k²) + 9.3 = 12.3

⇒ √(5 + k²) = 12.3 - 9.3 = 3

By squaring on both sides,

⇒ [√(5 + k²)]² = 3² = 9

⇒ 5 + k² = 9

⇒ k² = 9 - 5 = 4

⇒ k = √4 = ± 2 (answer - D).