5log (x+1) + 5log (x-3) = 1

Bab Logaritma
Matematika SMA Kelas X

⁵log (x + 1) + ⁵log (x - 3) = 1
⁵log ((x + 1) (x - 3)) = ⁵log 5
x² - 2x - 3 = 5
x² - 2x - 3 - 5 = 0
x² - 2x - 8 = 0
(x - 4) (x + 2) = 0
x - 4 = 0
x = 4

x + 2 = 0
x = -2

x - 3 > 0
x > 3

maka, x = 4