[tex](a,b,c)d.p(3,5,7)=\ \textgreater \ \frac{a}{3} = \frac{b}{5} = \frac{c}{7} =k \\ =\ \textgreater \ a=3k \\ =\ \textgreater \ b=5k
\\ =\ \textgreater \ c=7k \\ a+c=2b=\ \textgreater \ 3k+7k=2*5k=\ \textgreater \ 10k=10k=\ \textgreater \ a+c=2b
[/tex]
[tex]a^2-b^2+c^2=297=\ \textgreater \ 3k^2-5k2+7k^2=297 \\ 9kk -25kk+49kk=297=\ \textgreater \ 33kk=297 \\ =\ \textgreater \ kk=9=\ \textgreater \ k=3 \\ a=3k=3*3=9 =\ \textgreater \ a=9
\\ b=5k=5*3=\ \textgreater \ b=15
\\ c=7k=7*3=\ \textgreater \ c=21
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