Question

aratati ca nr c=(2la puterea40+2la puterea 39+2 la puterea38) : 7 este patrat perfect .

Answer 1

[tex]c=(2^{40}+2^{39}+2^{38}):7 \\ Dam~factor~comun~pe~cel~mai~mic,~2^{38}~si~va~rezulta: \\ c=2^{38}(2^2+2+1):7 \\ c=2^{38}(4+2+1):7 \\ c=2^{38}*7:7 \\ c=2^{38} \\ c=(2^{19})^2=> \\ =>c=p.p[/tex]