Răspuns:
✳ Un număr NU este patrat perfect daca poate fi scris ca un produs de de doua numere naturale consecutive
[tex]\bf 5^{34 }+ 5^{17} = 5^{17}\cdot \big(5^{34-17} +5^{17-17} \big) = 5^{17}\cdot \big(5^{17} +5^{0} \big)=[/tex]
[tex]\red{\bf 5^{17}\cdot \big(5^{17} +1 \big) ~~nu ~este~patrat ~perfect}[/tex]
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[tex]\bf 25^{47}\cdot 49^{17} = \big(5^2\big)^{47} \cdot\big(7^2\big)^{17}=[/tex]
[tex]\bf \big(5^{47}\big)^{2} \cdot\big(7^{17}\big)^{2}=\pink{\Big(5^{47} \cdot7^{17}\Big)^{2}\implies patrat ~perfect}[/tex]