Question

Найдите 5 член арифметической прогрессии: 1). 19. 15. 11... 2). -1. 3. 7..

Answer 1

1) 19/15/11/7/3.......

2)-1/3/7/11/15

Answer 2

1)

a1 = 19

a2=15

d = a2-a1 = 15-19 = -4

a5 = a1+4d = 19 + 4(-4) = 3

______________________

2)

a1 = -1

a2 = 3

d = 3-(-1) = 4

a5 = a1+4d = -1+4*4 = 15