Question 2; how do i solve it?
1 answer:
You might be interested in
Not necessarily. 
and 
may be linearly dependent, so that their span forms a subspace of 
that does not contain every vector in .
For example, we could have
and 
. Any vector 
of the form 
, where 
, is impossible to obtain as a linear combination of these and , since
unless
and 
.
For example, we could have
unless
