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**1. Homework Statement**

given a number of four ciphers ABCD and another four cipher number CDAB get the values of A,B,C,D if we know that 2x (ABCD)=CDAB-5

**2. Homework Equations**

2X (ABCD)=CDAB-5

**3. The Attempt at a Solution**

no idea.. i have try by brute force but got no results only incongruences , for example B=-3 or similar here '2 x' means multiplication