Odpowiedzi

2009-10-14T18:54:10+02:00
A) 2*log(x)-log(2)=log(8)

zal x>0
D=(0,∞)
logx²-log2=log8
log(x²/2)=log8
x²/2=8
x²=16
x=4∈D v x=-4∉D
b) log(x+24)+log(x-24)=log(100)

zal.
x+24>0 ∧x-24>0
x>-24 ∧ x>24 →x>24
D=(24,∞)
log(x+24)(x-24)=log(100)
(x+24)(x-24)=100
x²-576=100
x²=676
x=-26∉D v x=26∈D
c)