1. The problem statement, all variables and given/known data See image. a) and b) have been solved. The problem is c) 2. Relevant equations 3. The attempt at a solution I really have no idea where to begin. For the three systems given there are solutions x in range(A) for system 1 and 2 but not for 3. Therefore I have been trying to spot some obvious difference between system matrix A of system 2 and 3 but I cannot think of any clearly different property that could be linked to b. Any hint just to get me started would be much appreciated.