Question 371206
Getting a zero for the determinant of the coefficient matrix is not enough to say that it has no unique solution, or that it has no solution.  To know which one is the real situation, you have to go back to the original system:  The 2nd equation can be written as -4*(7x - 2y) = 7, or 7x - 2y = -7/4.  Direct substitution into the top equation gives 15 = -7/4, a contradiction.  Hence the system has no solution, or inconsistent.