Find a system of linear equations corresponding to the following augmented matrices:
(a)
2 0 |0
3 −4 |0
0 1 |1
(b)
3 0 −2 |5
7 1 4 |−3
0 −2 1 |7
(c)
7 2 1 −3 |5
1 2 4 0 |1
(d)
1 0 0 0 |7
0 1 0 0 |−2
0 0 1 0 |3
0 0 0 1 |4