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.