jika x1 dan x2 solusi dari persamaan 3.9x + 9^1-x = 28

Eksponen

Misal :
9^x = a

3 . 9^x + 9^(1-x) = 28
3a + 9/a = 28 ... Kalikan a
3a² - 28a + 9 = 0
(3a - 1)(a - 9) = 0
a = 1/3 atau a = 9

a = 1/3
9^x = 3^-1
3^2x = 3^-1
2x = -1
x = -1/2

a = 9
9^x = 9
x = 1

NiLai x yg memenuhi :
x1 = -1/2
x2 = 1