3. One process for encoding a secret message is to use certain matrices whose entries are integers and whose inverse also has integer entries. To do this, take a message,assign

a number to each letter (e.g. a=1, b=2, etc. and space =27) and arrange the numbers in a matrix from left to right in each row dropping to the next row each time you reach the end of a row. Use 27's to fill in the needed empty entries and encode the message by multiplying on the right by your encoding matrix B. (a) Suppose that you know the encoding matrix B and have received a string of numbers which represent an encoded message. What would need to be done to now decode the message? (b) Suppose the encoding matrix is the matrix B entered earlier. Suppose that you receive the following message that was encoded using the matrix B. Use Matlab to find the decoded matrix and write it on your paper. Now decode the message and write it on your paper. Encoded message =47, 49, -19, 257, 487, 10, -9, 63, 137, 236, 79, 142, -184, 372,536, 59, 70, -40, 332, 588 To get started, arrange the numbers into a matrix of 5 columns (the size of B).