Yeah that looks right, so now just clear the rest of the second row so that the 1 in row 2 is the only number in that column.
10. b) in augmented matrix form
1 -2 1 -4 1
1 3 7 2 2
1 -12 -11 -16 5
1 -2 1 -4 1
0 2 -1 4 -1 (row I*-1 + row II)
0 12 11 16 -5 (row I*-1 + row II)
kinda stuck at this point, do I simply divide row II by 2 to get a leading 1?
I got this by doing so:
1 -2 1 -4 1
0 1 -1/2 2 -1/2
0 12 11 16 -5
Am I on the right track?