✔ 最佳答案
(1) 7x ≡ 19 (mod 31), x = ?
解:
7x ≡ 19 (mod 31) ---(1)
31x ≡ 0 (mod 31) ---(2)
(1)×5 - (2),得:
4x ≡ 95 (mod 31)
4x ≡ 2 (mod 31) ----(3)
(3)×8 - (2),得:
x ≡ 16 (mod 31)
(2) 11x ≡ 68 (mod 69), x = ?
解:
11x ≡ 68 (mod 69) --(1)
69x ≡ 0 (mod 69) ---(2)
(1)×7 - (2),得:
8x ≡ 476 (mod 69)
8x ≡ 62 (mod 69)
4x ≡ 31 (mod 69) ---(3)
(2) - (3)×17,得:
x ≡ -527 (mod 69)
x ≡ 25 (mod 69)