Hello,

I am a bit confused about this one:

a + b + 2c = 12

3a - 3b -c = 3

2a - 1b - 6c = 24

The matrix

1 1 2

3 -3 -2

2 -1 6

In the lesson is said the row echelon form of the matrix is

1 1 2 = 12

0 -6 7 = -33

0 0 6 = 18 (getting 16.5 here)

From my calculation c is not 18 but 16.5 because the last row for me is

0 0 5.5

Am I doing something wrong?

Thanks

Carlo