Using the mapping 0 rightarrow 01 rightarrow 1 2 rightarrow

Using the mapping 0 rightarrow 0.1 rightarrow 1, 2 rightarrow 2.... 9 rightarrow 9, 10 rightarrow A, 15 rightarrow B, 20 rightarrow C, 25 rightarrow D, .... 135 rightarrow Z, 27 rightarrow and the matrix A below, a message has been encoded for students taking this exam. A = |1 0 -1 1 0 2 3 1 5 1 1 0 -1 1 10 2 3 1 1 1 1 0 -2 1 3| The encoded message (to be placed in a vector format) is How would you decode the message? Be as complete as possible. Give all the entries of the matrix representing the decoded message. What is the actual message?

Solution

A=[1 2 1 2 1;0 3 0 3 0;-1 1 -1 1 -2;1 5 1 1 1 ;0 1 10 1 3]

B=[289 216 -83 397 402; 550 390 -255 820 1615;377 396 13 665 950; 361 381 -7 342 708; 350 330 -50 280 850]

M= linsolve(A,B.\')%% B^T=AM,B is encoded message%%

ans =

105 75 27 30 35
45 100 105 27 10
30 120 80 50 65
27 30 27 100 100
10 95 6 27 30

which is equivalent to THE_ANSWER_TO_6E_IS_FALSE