Question

Let Q be the nxn real matrix in which each entry is 1. Show that det(Q-nIn)=0

Answer 1

Given: Q is an nxn real matrix and each entry is 1.
Theorem 3.4 states that if a row/column of A consists entirely of zeros, then det(A)=0

Answer 2

Ok. It's a square matrix. The In which is the identity matrix is one.
Identity 3 means a 3 x 3 matrix like this

Answer 3

so I'm just dealing with det(Q-n). if Q is an n x n matrix with each entry as one... It may look something like this