suma gauss: 1+2+3++a+49= 1+2+3+a+64= 1+2+3+a+154= 1+2+3+a+137=

Răspuns :

[(1+49)*49]÷2=[(1+64)*64]÷2=[(1+154)*154]÷2=[(1+137)*137]÷2=
(50*49)÷2=(65*64)÷2=(155*154)÷2=(138*137)÷2=
1. 49(49+1):2=1225
2. 64(64+1):2=2080
3.137(137+1):2=18908
Sper ca te-am ajutat