Question

дорешать арифм.прогр.

Answer 1

{2a1+2d=12

{a1+3d=12

 

 

{a1=12-3d

{24-6d+2d=12

{24-4d=12

{-4d=  -12

{d=3

{a1=3 

 

 

S10=(2*3+3*9)/2*10     =33*5 =  165