2 -1 3 1. Consider the matrix A = -4 2 k 4 -2 6 a) If A is the coefficient matrix of a homogeneous system of linear equations, determine the number of equations and the number of variables. b) If A is the coefficient matrix of a homogeneous system of linear equations, find the values of k such that the system is consistent. 2. Solve the system using Gaussian elimination with back-substitution. X1 - 3x3 = -2 3x1 + X2 - 2X3 = 4 2x1 + 2x2 + X3 = 4