# Math

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Find the value of x:

20x ≡ 9 (mod 15)

• Math -

Let x=1
20 ≡ 5 (mod 15)

As x increases by 1, the residue increases by 5, so no integer value of x satisfies the equation.

If you allow rational values for x, then it is easy to find many such x's: 9/20 comes to mind first...

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