How to solve matrix system?

[denfaro]

Hi! I am a beginner in matrices. I solved this questıon but I am not sure from my answer and I don't have the answer key. So could you help for the answer .

 

[Romsek]

a) [MATH]x = \begin{bmatrix}1\\2\\1\\0\end{bmatrix}t + \begin{bmatrix}0\\0\\-1\\3\end{bmatrix}[/MATH]
b) [MATH]null(A) = \begin{bmatrix}1\\2\\1\\0\end{bmatrix}[/MATH]
c) you can figure that one out w/o answer key

 

[denfaro]

a) [MATH]x = \begin{bmatrix}1\\2\\1\\0\end{bmatrix}t + \begin{bmatrix}0\\0\\-1\\3\end{bmatrix}[/MATH]
b) [MATH]null(A) = \begin{bmatrix}1\\2\\1\\0\end{bmatrix}[/MATH]
c) you can figure that one out w/o answer key

Thanks for your help .