Question

3x+1, 7x, 10x+8. (barisan geometri) x=?

Answer 1

Geometri = u3/u2 = u2/u1

(10x + 8) / (7x) = 7x / (3x +1)
(10x+8)(3x+1) = (7x) (7x)

30x² + 10x  + 24x + 8 = 49x²
34x + 8 = 49x² - 30x²
19x² - 34x - 8
( 19x + 4) ( x - 2)
ambil positif aja dah x = 2
3x + 1 = 6+1 = 7
7x = 14
10x + 8 = 28

7, 14, 28...geometri dengan rasio 2