Please answer this question in Linear Algebra Matrices I nee

Please answer this question in Linear Algebra (Matrices), I need them ASAP

Let A = [3 4 2 1], B = [2 3 -1 0 1 5], I = [1 0 0 1], x = [1 -3]. Compute (A - I) B^T. Compute the vector Ax, and then find its length, ||Ax||. Are the columns of b orthogonal? Explain why or why not.

Solution

A= [ 3 2 I = [1 0

4 1], 0 1]

A-I = [ 3-1 2-0 = [2 2

   4-0 1-1] 4 0]

B = [2 0 B^T =[2 3 -1

3 1 0 1 5]

-1 5]

(A-I)*B^T = [2 2] *   [2 3 -1] = [2 x 2 + 2 x 0   2 x 3 + 2 x 1   2 x (-1) + 2 x 5]

[4 0] [0 1 5] [4 x 2 + 0 x 0 4 x 3 + 0 x 1   4 x (-1) + 0 x 5]

= [4 8 8]

[8 12 -4]