Question

a) 1+2+3+4+...+79
b) 3+6+9+12+...+129

urgent (prin suma lui gauss va rog)​

Answer 1

Explicație pas cu pas:

A.......79*80:2=79*40=3160

B......(1*3)+(2*3)+..........+(43*3)=3*(1+2+3+.......43)=3*(43*44:2)=3*22=3*946=2838