Răspuns :
[tex]\displaystyle\bf\\81^{17}\cdot7^4=(3^4)^{17}\cdot(7^2)^2=3^{68}\cdot(7^2)^2=(3^{34})^2\cdot(7^2)^2= (3^{34}\cdot7^2)^2=patrat~perfect.[/tex]
[tex]\displaystyle\bf\\81^{17}\cdot7^4=(3^4)^{17}\cdot(7^2)^2=3^{68}\cdot(7^2)^2=(3^{34})^2\cdot(7^2)^2= (3^{34}\cdot7^2)^2=patrat~perfect.[/tex]