Write the set of solutions of
x≡ 5 (mod 24)
x≡ 17 (mod 18)
if any, as the solutions to a single congruence
x≡ 5 (mod 24)
x≡ 17 (mod 18)
if any, as the solutions to a single congruence
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x≡ 5 (mod 24)
<==> x≡ 5 (mod 3) and x≡ 5 (mod 8)
<==> x≡ 2 (mod 3) and x≡ 5 (mod 8)
x≡ 17 (mod 18)
<==> x≡ 17 (mod 9) and x≡ 17 (mod 2)
<==> x≡ 8 (mod 9) and x≡ 1 (mod 2)
Since x≡ 2 (mod 3) and x≡ 8 (mod 9) ==> x≡ 8 (mod 9),
and x≡ 5 (mod 8) and x≡ 1 (mod 2) ==> x≡ 5 (mod 8),
The above system with non-relatively prime moduli does have a solution,
having reduces it to x≡ 8 (mod 9) and x≡ 5 (mod 8).
With a little effort, we see that x ≡ 53 (mod 72) is the general solution.
I hope this helps!
<==> x≡ 5 (mod 3) and x≡ 5 (mod 8)
<==> x≡ 2 (mod 3) and x≡ 5 (mod 8)
x≡ 17 (mod 18)
<==> x≡ 17 (mod 9) and x≡ 17 (mod 2)
<==> x≡ 8 (mod 9) and x≡ 1 (mod 2)
Since x≡ 2 (mod 3) and x≡ 8 (mod 9) ==> x≡ 8 (mod 9),
and x≡ 5 (mod 8) and x≡ 1 (mod 2) ==> x≡ 5 (mod 8),
The above system with non-relatively prime moduli does have a solution,
having reduces it to x≡ 8 (mod 9) and x≡ 5 (mod 8).
With a little effort, we see that x ≡ 53 (mod 72) is the general solution.
I hope this helps!