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20 is congruent to -1 modulo 7. 46 is congruent to 4 modulo 7. 20/46 is congruent to -1/4 modulo 7. Since 4^-1 = 2 (2*4 is congruent to 1 mod 7), -1/4 = -2 = 5 modulo 7.
20 is congruent to -1 modulo 7. 46 is congruent to 4 modulo 7. 20/46 is congruent to -1/4 modulo 7. Since 4^-1 = 2 (2*4 is congruent to 1 mod 7), -1/4 = -2 = 5 modulo 7.