prove, that if sqr(a) + sqr(b) divides on 7, then a + b divides on 7 too
how can i prove, that if `sqr(a) + sqr(b)` divides on 7, then a + b divides on 7 too.
i'm thinking on it whole day...

Thanks
prove, that if sqr(a) + sqr(b) divides on 7, then a + b divides on 7 too
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how can i prove, that if `sqr(a) + sqr(b)` divides on 7, then a + b divides on 7 too.
i'm thinking on it whole day...

Thanks