Chapter 7 - Symmetric Matrices and Quadratic Forms - 7.1 Exercises - Page 401: 6

Since the matrix is not square, it is not symmetric.

The definition of a symmetric matrix is as follows a symmetric matrix is a matrix A such that $A^{T}$ = A. A symmetric matrix must be square. Since the matrix has 3 rows and 4 columns, the matrix is no square. Since the matrix is not square, it is not symmetric.