Question for null space of a matrix

[shiecldk]

Let A be a 4×3 matrix and let
[tex]c=2a_{1 }+a_{2}+a_{3}[/tex]

(a) If N(A) = {0}, what can you conclude about the solutions to the linear system [tex]Ax = c[/tex]?

(b) If N(A) ≠ {0}, how many solutions will the system [tex]Ax = c[/tex] have? Explain.