N 14 72 I 1 O P Q 15 16 17 18 19 3 4 5 6 7 8 9 10 11 12 13 To code a secret message we can use the function f x 2x 1 Take each letter of the message and input its corresponding number into this function By doing this we get a coded message What is the inverse of f x 2x 1 f x R S T U V W X Y Z 20 21 22 23 24 25 26 27 51 3 29 39 47 11 37 I