中 4 數學題 (about log )

2007-11-21 9:57 pm

log (x+16) - log (x-2)=1

請給過程,謝謝

回答 (3)

2007-11-21 10:05 pm

✔ 最佳答案

log (x+16) - log (x-2)=1
log[ (x+16) / (x-2)]=1
(x+16) / (x-2)=10
(x+16) =10(x-2)
x+16 =10x-20
9x =36
x =4

👍 0 👎 0

2007-11-22 12:05 am

log (x+16) - log (x-2)=1
=> log [(x+16)/(x-2)] = log 10
=> (x+16)/(x-2) = 10
=> x+16 = 10(x-2)
=> 9x = 36
=> x = 4

👍 0 👎 0

2007-11-21 10:16 pm

log(x+16)-log(x-2)=1
log[(x+16)/(x-2)]=1
log[(x+16)/(x-2)]=log10
(x+16)/(x-2)=10
x+16=10(x-2)
x+16=10x-20
-9x=-36
x=4

👍 0 👎 0