vector space intersection

given the vector spaces that are subspaces of the vector space (meaning ), then the intersection of and is defined as:
given vector spaces , to find the intersection the steps are:
  1. construct the matrix and find the basis vectors of its nullspace.
  2. for each basis vector construct the vector .
  3. the set consistute the basis for the intersection space .
given , we find the basis and dimension of :
to find we need to write and as a system of equations
to find the corresponding equations of we reduce the following matrix:
and so , and:
now to find the corresponding equations of we reduce the following matrix:
and so , and:
we put these equations in a matrix and reduce it:
which gives us:
and so and