Linear operators - basis and dimension

Question

Question:

Linear Operators - Basis and Dimension - year 4

Question (1)

Find a basis and dimension of the subspace W of R⁴ generated by the vectors
( 1 , - 4 , - 2 , 1 ) , ( 1 , - 3 , - 1 , 2 ) , ( 3 , - 8 , - 2 , 7 ) .

Extend it to find the basis of R4 .

Question (2)

Determine a basis and the dimensions of the Subspace of M2(R) generated by the

Matrices [ 2 -10 ] , [ 3   3 ] , [ 2 -4 ] , [ 2 -14 ]
               [ -8 4 ]    [ -3 15]   [ -5 7]    [-10  2 ]