Question

insira seis meios aritméticos entre 7 e -28

Answer 1

a1=7
an=-28
razão=?
n=8

an=a1+(n-1).r
-28=7+(8-1).r
-28=7+7r
-28-7=7r
r=-35/7
r=-5

(7,2,-3,-8,-13,-18,-23,-28...)

Answer 2

    a1 = 7 ; an = - 28 ; n = 8
  

7 +  7r = - 28
     7r = - 28 -7
  r = - 5

( 7, 2, - 3, -8, - 13, - 18, - 23, - 28, - 33, - 38 , ...)