Question

Tentukan x !
a. log (x-3) + log (x+1) = log 5
b. 14log (x^2 - x - 6) = 1

Pake cara ya :)

Answer 1

A.  log(x - 3) + log(x + 1) = log5
     log(x - 3)(x + 1) = log5
     (x - 3)(x + 1) = 5
     x^2 - 2x - 3 = 5
     x^2 - 2x - 8 = 0
     (x - 4)(x + 2) = 0
     x = 4 atau x = -2

b. 14log (x^2 - x - 6) = 1
   14 log (x^2 - x - 6) = 14 log 14
     x² - x - 6 = 14
     x² - x - 20 = 0
    (x - 5)(x + 4) = 0
     x = 5 atau x = -4