Math 2602 A1 - A3                                                                               Homework #12
                                             Due Tuesday, November 29, 2005


     a)  Sketch the region S in 3-space determined by the inequalities below.

                      6x + z  <  18
                      y  <  5
                      z  <  6
                      2x + 2y + z  <  18
                      x . y , z  >  0















  

 b)  Find the maximum value of  f( x , y , z )  =  x + 2y + z on S.