Hi again,
From practice questions for upcoming test:
Solve the linear congruence: 4x 5 (mod 11)
First find the inverse, 11 = (2)(4) + 3; 4 = (1)(3) + 1
so 3 = 11 + (-2)(4) and 1 = 4 - 3 = 4 - [ (1)(11) + (-2)(4)] = (-1)(11) + (3)(4)
So 4(3) 1 (mod 11) and 4(15) 5 (mod 11)
Therefore the solution is x = 15.
Is the above correct? Or since 15 -11 = 4 and 0 < 4 < 11, would 4 be a more correct answer?