Respuesta :

General Arithmetic Progression:  

[tex]\boxed { \boxed {T_n= a_1 + d(n - 1)}}[/tex]


21 , 16 , 11 , 6 ,  1 , -4
  
[tex]a_1 = 21, d = -5[/tex]

[tex]T_n = 21 -5(n - 1)[/tex]

[tex]T_n = 21 -5n + 1[/tex]

[tex]T_n = 22 -5n[/tex]

[tex]\boxed { \boxed {\text {Answer: } T_n = 22 -5n }}[/tex]


-3, 5, 13, 21, 29, 39

[tex]a_1 = -3, d = 8[/tex]

[tex]T_n = -3 + 8(n - 1)[/tex]

[tex]T_n = -3 + 8n - 8[/tex]

[tex]T_n = 8n - 11[/tex]

[tex]\boxed { \boxed {\text {Answer: } T_n = 8n - 11}}[/tex]


44, 16, -12, -40, -68

[tex]a_1 = 44, d = -28[/tex]

[tex]T_n = 44 - 28(n - 1)[/tex]

[tex]T_n = 44 - 28n + 28[/tex]

[tex]T_n = 72 -28n[/tex]

[tex]\boxed { \boxed {\text {Answer: } T_n = 72 - 28n}}[/tex]

Answer:

The given sequences are

[tex]21, 16, 11, 6, 1, -4...\\-3, 5, 13, 21, 29, 37...\\72, 44, 16, -12, -40, -68...[/tex]

The first sequence is decreasing by a difference of 5, that is

[tex]21-5=16\\16-5=11\\11-5=6\\6-5=1\\1-5=-4\\-4-5=-9\\-9-5=-14[/tex]

So, the next two terms are -9 and -14.

The second sequence is increasing by a difference of 8, that is

[tex]-3+8=5\\5+8=13\\13+8=21\\21+8=29\\29+8=37\\37+8=45\\45+8=53[/tex]

So, the next two terms are 45 and 53

The third and last sequence is decreasing by a difference of 28, that is

[tex]72-28=44\\44-28=16\\16-28=-12\\-12-28=-40\\-40-28=-68\\-68-28=-96\\-96-28=-124[/tex]

So, the next two terms of this sequence are -96 and -124.