https://www.youtube.com/channel/UCSoVyBb75Mf9o_eZGuKa2HQ

]]>For your divisibility problem, I would naturally reduce all of the coefficients modulo 7 (choosing equivalent coefficients between 0 and +6), which immediately gives me the answer. While, for me, finding non-trivial values for x and y so that the given expression is divisible by 7 and then substituting those numbers into each expression takes a lot more time.

But the fact that different methods will work is one of the beauties of mathematics!

Thank you for the post!

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