Diketahui 2x, 4x+1 dan 14 merupakan tiga suku pertama suatu barisan aritmatika. Suku ke 10 barisan tersebut adalah...
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tolong bantuannya :)
2x, 4x + 1, 14
U₁ U₂ U₃
beda = beda
U₂ - U₁ = U₃ - U₂
4x + 1 - 2x = 14 - ( 4x + 1 )
2x + 1 = 14 - 4x - 1
2x + 1 = 13 - 4x
2x + 4x = 13 - 1
6x = 12
x = 2
U₁ = 2x = 2.2 = 4
U₂ = 4x + 1 = 4.2 + 1 = 6 + 1 = 7
U₃ = 14
4, 7, 14 a + b + c
+3 +7 3a + b
+4 2a
Cari a Cari c
2a = 4 a + b + c = 4
a = 4/2 = 2 2 - 3 + c = 4
Cari b -1 + c = 4
3a + b = 3 c = 4 + 1
3.2 + b = 3 c = 5
6 + b = 3
b = 3 - 6
b = -3
Un = an² + bn + c
= 2n² - 3n + 5
U₁₀ = 2.10² - 3.10 + 5
= 2.100 - 30 + 5
= 200 - 25 = 175
[answer.2.content]
