The augmented matrices of three systems of linear equation are given in row echelon form below.

(i)
|1 0 2 1|
|0 0 1 2|
|0 0 0 1|

(ii)
|1 0 2 1|
|0 1 −1 2|
|0 0 1 1|

(iii)
|1 0 2 1|
|0 0 1 2|
|0 0 0 0|

One of the systems has no solutions, one has one solution, and one has an infinite number of solutions. Identify which is which and solve the two that have solutions.


*give ur workings and answer.