Question

Tolong dong, pakai caranya :)

Answer 1

7. ³log(x+1) = 1 + ⁹log (x-1)
³log (x+1)= ³log 3 + ³log (x-1)¹/²
(x+1) = 3√(x-1) dgn syarat x+1 > 0 atau x -1 > 0 --> x > 1
kuadrat kan kedua ruasnya
(x+1)² = 3² (√(x-1))²
x² + 2x + 1 = 9 (x-1)
x² + 2x + 1 = 9x - 9
x² + 2x - 9x + 1 + 9= 0
x² - 7x + 10 = 0
a = 1 , b = - 7 , c = 10
. 
x₁. x₂ = c/a =10/1
x₁ x₂ = 10

8. log(x²-24) = log { x (¹⁶/₁₅)⁷ (²⁴/₂₅)⁵ (⁸¹/₈₀)³}
log (x² -24) = log (x (2))
x²-24 = 2x  dgn batas x²-24 > 0  atau x² > 24

x² -24 = 2x
x² - 2x - 24 = 0
(x-6)(x+4) = 0
x = 6 atau x = - 4 (tidak memenuhi krn (-4)² < 24)
HP  x = 6