1. Selesaikan
a. ²log (2x + 5) – 2 ²log 2x = 2
2. ²log (x² – 2x + 1) = ²log (2x² – 2)
Jawaban Terkonfirmasi
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