👤
a fost răspuns

2+5+8 +11+14+17...302

Răspuns :

Nicol10Anton
2+5+8+...+302=
=(3×0+2)+(3×1+2)+(3×2+2)+...+(3×100+2)=
=3×(0+1+2+...+100)+2×101=
=3×[100×(100+1)]÷2+2×101=
=3×(100×101)÷2+2×101=
=3×(50×101)+2×101=
=3×50×101+2×101=
=101×(3×50+2)=
=101×(150+2)=
=101×152=
=15352
Dfabiangeorgian
2+5+8+...=(3+6+8+...+303)-1
.................=[306x(303:3)]-1
....................=[306x101)-1
......................=30906-1
.......................=30905
SPER CA TE-AM AJUTAT !

Alte intrebari