parmenides51 12.06.2020 00:31 Let $p$ be a prime number. Show that $7^p+3p-4$ is not a perfect square.
Jjesus 12.06.2020 07:43 $M=7^p+3p-4$ If $p=3 \rightarrow M=348$ If $p\equiv 1(mod3) \rightarrow M\equiv 6(mod9)$ If $p\equiv 2(mod3) \rightarrow M\equiv 6(mod9)$