Let W = { [a+b a-b a+2b] , a,b are in R} its a 3*1 matrix, a+b , a-b and a+2b are actually the first elements of three different rows. Find any three spanning sets for W? I managed to find one,

a (1 1 1) + b(1 1 1) , both of these are also 3*1 matrices where each 1 is the first element of the first three rows.

How do i find the other two ?

Sorry about my notation.

PLease help.