(a) Use Gauss-Jordan elimination to solve the system of linear equations + X 7 - * + 2x, - 5X, = 1, 3x + 4X, - 2x + 6X - 9X, = R+1, 2x - 4X3 + 6x, + 2x5 = 4. (b) Consider the system of linear equations 1 p+1 2 3 - P 3 p -p 3p+2 x, where p and q are constants. Use elementary row operations to find all the value(s) of p and q, if any, such that this system has (i) a unique solution. (ii) infinitely many solutions. (iii) no solution