Answer:
[ 1 0]
[ 0 1]
Explanation:
to obtain a matrix product of B * A we have to multiply the first element of the first row of B by the first element of the first column of A and to this add the second element of the first row of B by the second element of the first row of A, so we will get the first term of the resulting matrix
For each term of the resulting matrix, follow this form
[(B11*A11)+(B12*A21) (B11*A12)+(B12*A22)]
[(B21*A11)+(B22*A21) (B21*A12)+(B22*A22)]
[1/4 1/2] * [2 2]
[1/4 -1/2] [1 -1]
[ (1/4)(2)+(1/2)(1) (1/4)(2)+(1/2)(-1) ]
[ (1/4)(2)+(-1/2)(1) (1/4)(2)+(-1/2)(-1) ]
[ 1/2+1/2 1/2-1/2]
[ 1/2-1/2 1/2+1/2]
[ 1 0]
[ 0 1]