Răspunsuri

2014-10-28T19:56:13+02:00
A= 3(1/21+1/20+1/19)·1/39 =[(20·19 +21·19 +21·20) /(21·20·19)] ·1/13 = (380+399+420)/(21·20·19) ·1/13 =1199·/(21·20·19·13) nu este  patrat perfect !!!!