Diketahui barisan Aritmatika U2= 5 dan U4+U6= U28 hitunglah U9 = ? Pakai cara

U2 = a + b = 5
a = 5 - b

U4 + U6 = 28
a + 3b + a + 5b = 28
2a + 8b = 28
2(5 - b) + 8b = 28
10 - 2b + 8b = 28
10 + 6b = 28
6b = 28 - 10
6b = 18
b = 18/6
b = 3

a = 5 - b
a = 5 - 3
a = 2

U9 = a + 8b
U9 = 2 + 8.3
U9 = 2 + 24
U9 = 26

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