Question

Tentukan nilai x dalam persamaan eksponen berikut
a. 2^2x - 10 . 2x + 16 = 0
b. 9^x + 8 . 3^x - 9 = 0

Answer 1

A. dengan memisalkan 2^x = a
==> a² - 10a + 16 = 0
==> (a - 8)(a - 2) = 0
==> a = 8 dan a = 2
==> 2^x = 8 = 2³
==> x = 3
dan
==> 2^x = 2 = 2¹
==> x = 1


b. dengan memisalkan 3^x = a
==> a² + 8a - 9 = 0
==> (a + 9)(a - 1) = 0
==> a = -9 dan a = 1
==> 3^x = -9
==> x = ³ log (-9)
dan
==> 3^x = 1
==> 3^x = 3°
==> x = 0