I dont think I understand what this question is asking, if someone could explain what it means with its explanation it would help a lot.

solve the 2 systems

x1 + 2x2 - 2x3 =1 x1 + 2x2 - 2x3 = 9

2x1 + 5x2 +x3 = 9 2x1 + 5x2 +x3 = 9

x1 + 3x2 + 4x3 = 9 x1 + 3x2 + 4x3 = -2

the question gives this explanation

by doing elimination on a 3x5 augmented matrix and the performing two back substitutions.

I thought it meant to put the two systems together, but since the 2nd row of equations are the same there would only be 5, not 6 I would use so it would be 3x5.

1 2 -2 1

2 5 1 9

1 3 4 9

1 2 -2 9

1 3 4 -2

but then that would make 2 rows

0 0 0 x

and then wouldn't it be inconsistent. But the book has answers to the question so its not that. What is this question even asking me to do?