Solving Affine Cipher with Number Theory

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The discussion revolves around deciphering a text using the Affine Cipher, with initial equations derived from known letter mappings (C->A and B->T). The user attempts to solve the equations 2a+b=0 (mod 26) and a+b=19 (mod 26) but struggles with the results. They express frustration with obtaining a decipher equation that does not yield the expected letter mappings. Ultimately, the user resolves the issue independently, indicating a successful breakthrough in their solution process. The thread highlights the challenges and problem-solving involved in applying number theory to cryptography.
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Homework Statement



Decipher the following text

KQEREJEBCPPCJCRKIEACUZBKRVPKRBCIBQCARBJCVFCUPKRIOF KPACUZQEPBKRXPEIIEABDKPBCPFCDCCAFIEABDKPBCPFEQPKAZ
BKRHAIBKAPCCIBURCCDKDCCJCIDFUIXPAFFERBICZDFKABICBB
ENEFCUPJCVKABPCYDCCDPKBCOCPERKIVKSCPICBRKIJPKABI


Homework Equations



I know that C->A and B->T

The Attempt at a Solution



that means my two equations are:

2a+b=0 (mod 26)
a+b=19 (mod 26)

I must be solving these wrong. I need to get a decipher equation and I keep getting

d(k)=15(y-5) (mod 26) but that doesn't allow K->O like it should.
 
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Nevermind, I figured it out.
 

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