PLEASE SHOW STEP-BY-STEP

An affine cipher is a generalization of the Caesar cipher and has the following form: E(x)=(ax+b) "mod" 26, where x is the plaintext letter and E(x) is the ciphertext letter. Now, assume that a ciphertext has been generated using an affine cipher where the first and second most frequent letter in the ciphertext are B and U, respectively. Use the given information and what weve covered in class to break this code! Hint: You are being asked to solve for a and b using a system of linear equations.