Question

Jika a+2 , a-1 , a-7 membentuk barisan geometri , maka rasio nya adalah ...

ini gmna yah cara nya .. tolong bantuan nya yah teman

Answer 1

Verified answer

Deret Geometri

Un =

U1 = a = a + 2
U2 = ar = a - 1
U3 = ar² = a - 7







U1 = a + 2 = -5 + 2 = -3
U2 = a - 1 = -5 - 1 = -6
U3 = a - 7 = -5 - 7 = -12

r = U2/U1= -6/(-3( = 2

Jadi, rasio = 2.

Answer 2

Verified answer

[Barisan Geometri]

Perbandingan Rasio
U2/U1 = U3/U2
(a - 1)/(a + 2) = (a - 7)/(a - 1)
(a - 1)² = (a + 2)(a - 7)
a² - 2a + 1 = a² - 5a - 14
3a = -15
a = -5

Substitusi..
Rasio = U2/U1
Rasio = (a - 1)/(a + 2)
Rasio = (-5 - 1)/(-5 + 2)
Rasio = 2