+27 If a, b, and c are positive integers less than 13 such that:
2ab + bc + ca ≡ 0 (mod 13)
ab + 2bc + ca ≡ 3abc (mod 13)
ab + bc + 2ca ≡ 8abc (mod 13)
What is the remainder when a + b + c is divided by 13?
Thanks in advance!
+355 Hopefully this is helpful, https://web2.0calc.com/questions/hard-hard-hard. It might be wrong, and it might not answer them all, but i hope this helps
