For the matrix

,

consider the set

S={bR

3

:b=Axfor somexR

3

}.

An element ofS

has the formA

x

y

z

For the matrix 2 4 -8 A = -4 -4 12 , 1 2 -4 consider the set S:{bER3:h:Ax ferseme xERg}. :I: An element of S has the ferm A y , 1which can he written as the linear cembinetien ef vecters I , A y = 3| l Z Hall |@@ +2 l' ile e