If p is a unit vector and (x - p). (x + p) = 80 then the value of |x| is

Question

If \(\overrightarrow{p}\) is a unit vector and \((\overrightarrow{x}-\overrightarrow{p}).(\overrightarrow{x}+\overrightarrow{p})\) = 80 then the value of \(|\overrightarrow{x}|\) is

(A) \(4\sqrt{5}\)

(B) 7

(C) 8

(D) 9

Answer 1

Correct option is: (D) 9