How to solve it?

let x be a n x 1 vector such that x'x = 5, where x is the transpose of x. 27. Define A = I- 6X'X, Where T is the nth order identity matrix. Which of the following statement not true ? A2 A (A) (B) (C) (D) A2 = I Eigen values of A are unit modulo 1 Trace A = n - 25 um af entries in each row of A is 4.