Question

calculati sumele a)2+7+12+...+257
b) 5+10+15+...+195
9) /a1=-2; r=4.calculati A3.A6.A10.S10 =?
urgent va rog frumos​

Answer 1

a) 2+7+12+...+257

Nr termeni: (257-2):5+1=52 termeni

259×52/2= 13.468/2=6734 suma

b) 5+10+...+195

Nr termeni: (195-5)÷5+1= 39 termeni

200×39/2= 7.800 suma

c) nush acest subpunct, imi pare foarte rau.

Sper ca te-am ajutat cu sumele.