maths~matrix

In Gaussian elimination form:

圖片參考：http://i1191.photobucket.com/albums/z467/robert1973/Sep11/Crazyeqn1.jpg


From row 2, we can find out that for (E) to be consistent, b = 0.

2011-09-06 17:40:48 補充：
Yes, b = 1 is correct
In 2nd step, the 2nd row should be 0, 8, -2, b - 1 instead of b.
Then in last step, the 2nd row is 0, 0, 0, b - 1
So to make it consistent, b = 1 is a must.