Question

1. Selesaikan
a. ²log (2x + 5) - 2 ²log 2x = 2
2. ²log (x² - 2x + 1) = ²log (2x² - 2)

Answer 1

No 1
² log (2x + 5) - 2.²log 2x = 2
² log (2x + 5) - ² log (2x)² = ² log 2²
² log (2x + 5)/4x² = ² log 4
(2x + 5)/4x² = 4
2x + 5 = 4(4x²)
2x + 5 = 16x²
16x² - 2x - 5 = 0
(8x - 5)(2x + 1)
x = 5/8    x = -1/2
HP {5/8 ; -1/2} (karena semua bernilai positif pada logaritma)

no. 2
² log (x² - 2x + 1) = ² log (2x² - 2)
x² - 2x + 1 = 2x² - 2
2x² - x² + 2x - 2 - 1 = 0
x² + 2x - 3 = 0
(x -3) (x + 1) = 0
x = 3    x = -1

HP{3 ; -1}

jangan lupa kasih nilai maksimal ya