To solve this we are going to graph each one of the system of equations. The points in which the graphs of the tow equations intercepts will be the real solutions of the system of equations.
System A. Since the graph of the equations intercepts two times, we can conclude that the system has 2 real solutions.
System B. Since the graph of the equation don't intercept, we can conclude that the system has 0 real solutions.
System C. Since the graph of the equations intercepts two times, we can conclude that the system has 2 real solutions.