Which statement about this system of equations is true?

a. diagonal curve declines through (negative 7, 4 point 9), (negative 5, 3), (0, 0), (3, negative 2) and (6, negative 4).
b. a diagonal curve declines through (negative 7, 7 point 5), (negative 3, 5), (0, 3), (3, 1) and (7, negative 2).

1. the system has no solution.
2. the system has a unique solution at (0,0).
3. the system has a unique solution at (0,3).
4. the system has infinitely many solutions.