Please note: This question does not count for my grade. It comes from a final study guide. Can someone please verify I did it (part d) correctly? Thanks!
http://img267.imageshack.us/img267/1910/capturehaw.jpg
Attempt at Solution:
(a1+1)+(a2+2)t=0
This gives the system:
a1+1=0
a2+2=0
So,
a1=-1
a2=-2
So the set of all vectors for which L(a1,a2)=0 is:
N(L)={(a1,a2)|a1=-1 and a2=-2}

