Consider the following system of linear equations and answer the subsequent questions -2x1-12x2-17x3+12x4 = 1 -3x1-11x2-17x3+11x4 = 0 3x1+16x2+23x3-16x4 = -1 3x1+16x2+21x3-16x4 = 1 (a) Write the system as Ar = b for some matrix A and a vector b (b) Use Gaussian elimination to solve the system exactly; that is, do not convert fractions to decimals. Make sure to first find the row-echelon form of its augmented matrix and provide the general solution (c) Compute the rank of A