Với mọi a ; b $\epsilon$Z+
Edited by Oral31211999, 23-03-2013 - 11:34.
Edited by Oral31211999, 23-03-2013 - 11:34.
"If I feel unhappy,I do mathematics to become happy.
If I feel happy,I do mathematics to keep happy."
Alfréd Rényi
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