數學解救我吧

a. log x=log(a+y)-1
log x=log(a+y)-log10
log x=log[(a+y)/10]
x=(a+y)/10
a+y=10x
y=10x-a

b. log(s+t)=2log t+2
log(s+t)=2log t+2log10
log(s+t)=log(t^2)+log(10^2)
log(s+t)=log(t^2)+log100
log(s+t)=log[100(t^2)]
s+t=100(t^2)
s=100(t^2)-t
s=t(100t-1)


2011-07-28 17:00:35 補充：
c. (log5+2log2-1)/(2log4-log0.5)
=(log5+log4-log10)/(log16-log0.5)
=log(5X4/10)/log(16/0.5)
=log2/log32
=log2/(5log2)
=1/5

2011-07-28 17:00:47 補充：
d. (log8+3log5-2)/(2log5-log0.25)
=(log8+log125-log100)/(log25-log0.25)
=log(8X125/100)/log(25/0.25)
=log10/log100
=1/2

2011-07-28 17:01:02 補充：
如再有新問題, 請出新post

And I found your second question, posted yesterday as well, have the following fate:

很抱歉！
問題已經被發問者自行移除，請回上一頁。

I hope you would not erase the efforts exerted by the helpers here after reading the solution. That is very unfair to them.

嗯,我認為won******您應該再發問

在得到別人回答後,再追加與原題無關的問題是不合理的。即使你附出20點。