## (15 Points) Indicate the general rule for the arithmetic sequence with a3 = -4 and a8 = -29.

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(15 Points) Indicate the general rule for the arithmetic sequence with a3 = -4 and a8 = -29.

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Mathematics
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2021-07-21T21:34:06+00:00
2021-07-21T21:34:06+00:00 2 Answers
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## Answers ( )

Answer:General rule » -5n+11

Step-by-step explanation:a3 = a+2d = -4 …….(1)

a8=a+7d = -29……….(2)

(2)-(1) » 5d= -25

d = -25/5

. = -5

substitute d = -5 in ( 1)

» a-2×-5= -4

a-10 = -4

a = -4 +10

= 6

General rule » a +(n-1)d

» 6 +(n-1)×-5

» 6-5n+5

» -5n+11Step-by-step explanation:= – 4

= a* + (3- 1) d*

– 4 = a + 2d . . . . . . . . .(i)

= – 29

= a + ( 8 – 1) d

– 29 = a + 7d . . . . . . . . (ii)

subtracting equations (i) and (ii)

25 = 5d

d = -5

placing d = -5 in equation (i)

a – 10 = -4

a = 6

For an arithmetic Progtession

= a + (n – 1)d

= 6 + (n- 1)-5

= 6 – 5n + 5

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