Question

Suatu barisan aritmatika dengan suku pertamanya -15 dan suku kelimanya 1

A. Beda barisan
B. suku kesepuluh
C. 10 suku pertama

Answer 1

Diketahui:
U1 = -15
U5 = 1
Ditanya, abc
Jawab:
A. Beda barisan (b) =
U1 = a = -15
U5 = a+ (5-1) b = 1
__________________-
4b = -16
b = 4

B. U10= -15 + (10-1) 4
= 21

C. -15, -11, -7, -3, 1, 5, 9, 13, 17, 21

semoga membantu ^_^

Answer 2

Dik : rumus suku ke-n = a + b(n-1)
U1 = a = -15
U5 = a + 4b = 1

a)
a + 4b = 1
(-15) + 4b = 1
4b = 16
b = 4

b)
U10 = a + 9b = (-15) + 9(4) = -15 +36 = 21

c)
10 suku pertama yaitu, U1, U2, U3, U4, U5, U6, U7, U8, U9, U10

Un = a +b(n-1)
U1 = -15

U2 = (-15) + 1(4) = -11

U3 = (-15) + 2(4) = -7

U4 = -3
U5 = 1
U6 = 5
U7 = 9
U8 = 13
U9 = 17
U10 = 21

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minta bintangnya kakak ( *w*)/