Question

Aratati ca numarul c=(2 la puterea 40 +2 la puterea 39+2 la puterea 38):& este patrat perfect

Answer 1

[tex]c=(2^{40}+2^{39}+2^{38}):7\\ c=2^{38}(2^2+2+1):7\\ c=2^{38}\cdot 7:7\\ c=2^{38}=(2^{19})^2-patrat\ perfect[/tex]