Let c be a real number, and consider the system of quadratic equations
y = 6x^2 - 9x + c - x^2 - x
y = 5x^2 - 3x + x^2 + 2x
For which values of c does this system have:
(a) Exactly one real solution (x,y)
(b) More than one real solution?
(c) No real solutions?