Question

Efectuati: S1= 1+6+11+16+...+51 (5p)
S2= 6+9+12+15+...+60 (5p)
S3= 10+14+18+22+...+318 (5p)

Answer 1

Sper ca te am ajutat!!!!!!!

Answer 2

S1=1+6+11+…+51. Toti termenii sunt Multiplii de 5 +1 => 5x0+1+5x1+1+…+5x10+1=5x(1+2+..+10)+1+1+…+1(avem 10-0+1 de 1)=5x10x11:2+11=286

S2=6+9+..+60. Toti termenii sunt Multiplii de 3=>3x2+3x3+…+3x20=S2= 3x(2+…+20)=3x1344=4032

S3=10+14+…+318. Toti termenii sunt Multiplii de 4 +2 => 4x2+2+4x3+2+…+4x79+2=4x(2+3+..+79)+1+1+..+1( de 79-2+1 ori)=4x(2+3+…+79)+78