Question

Aratati ca numarul c=(2 la 40 + 2 la 39 + 2 la 38 ) :7 este patrat perfect
Urgentt coroanaaa

Answer 1

$2^{38} ( 2^{2} + 2^{1} +1):7= 2^{38} *7:76= 2^{38} = (2^{19})^{2} -p.p$