solve step by step

this is all the given question

13. Consider the following matrix with entries from E, E=[21379]E=[21578]E=[21568] (a) What is the determinant of E ? (b) Is E invertible modulo 26? Why or why not? (c) If E is invertible modulo 26, find its inverse modulo 26. (d) Use E to encrypt the message HELP. (e) What message or messages encrypt to XXXX? 14. Use a Hill cipher with key [35712] to encrypt the following message. Welcome to Cryptography. Decrypt the message. ZKYZR QHBDM JMPVX WLCGF MIXGM PKBUZ FHPCI XZTIW 15. Suppose you know both the plaintext "bean" and the corresponding ciphertext "oykh" for a Hill 2-cipher. You want to determine the inverse key and key, so that you can encipher \& decipher any further deciphered \& enciphered messages you might intercept [Known Plaintext Attack]. 16. We are assuming that we have a ciphertext message was that encrypted using a 22 Hill cipher and that we have "a crib". We Believe that ciphertext "UKJN" corresponds to plaintext word [Chosen Ciphertext Attack - Determine decryption key]. 17.A 22 Hill cipher encrypted the plaintext "SOLVED" to give the ciphertext "GEZXDS". Find the encryption matrix