To evaluate 23 x 54 (mod 7), we need to perform the multiplication first, which gives us 1242. Then, we take this number modulo 7 by finding the remainder when 1242 is divided by 7.
Dividing 1242 by 7 gives us a quotient of 177 and a remainder of 3. Therefore, 1242 is congruent to 3 (mod 7).
So, 23 x 54 (mod 7) is equivalent to 3 (mod 7). Therefore, the answer is 3.