Jawabanmu

2014-02-27T14:43:27+07:00
X-1, 2x-8, 5-x masing2 adalah U1, U2 dan U3

berdasarkan persamaan aritmatika, U3-U2 = U2-U1
maka,

5-x - (2x-8) = 2x-8 - (x-1)
5 - x - 2x +8 = 2x - 8 - x + 1
-3x +13 = x - 7
-4x = -20
4x = 20
x = 20/4
x = 5

1 1 1
2014-02-27T15:37:01+07:00
(2x-8)-(x-1)=(5-x)-(2x-8)
x-7=13-3x
x+4x=13+7
4x=20
x=20/4
x=5

1 5 1