(* Linear Algebra: Theory and Applications *)
(* Ward Cheney & David Kincaid *)
(* JBPub.com (c) 2008 *)
(* File: exp724.mat *)
(* Example 7.2.4      *)

A = {{1,4},{2,5},{3,6}}
b = {1,1,-2} 
E = Transpose[A].A
f = Transpose[A].b 
G = {E,f}
RowReduce[G]