Question

Ada yang bisa tidak? tolong bantu, ini buat belajar

Answer 1

Jawab:

Penjelasan dengan langkah-langkah:

Answer 2

Barisan geometri a, a+b, 4a+b+9
U₁ = a
U₂ = ar = a+b
U₃ = ar² = 4a+b+9

Barisan aritmatika a, a+b, 4a+b
U₃ = a + 2b = 4a+b
↓
a + 2b = 4a + b
a - 4a = b - 2b
-3a = -b
3a = b

Cari rasio barisan geometri
U₂/U₁ = ar/a
ar/a = (a+b)/a
r = (a+b)/a
r = (a+3a)/a
r = 4a/a
r = 4

Substitusi r = 4 ke suku ketiga barisan geometri
U₃ = ar²
a(4²) = 4a + b + 9
16a = 4a + b + 9
16a = 4a + 3a +9
16a = 7a + 9
16a - 7a = 9
9a = 9
a = 1

b = 3a
b = 3(1)
b = 3