logarithms

Question

how are you suppose to do with these kind of mathematical equations.

Log(10)=log(30)-log( )

Answer 1

Dear Yong,

 

If I understand the problem, what you are asking is what is x if

 

log(10) = log(30) - log(x) 

 

Whenever you see a "minus" sign in a logarithmic expression think "subtraction."  The given expression is mathematically identical to saying

 

10 = 30/x

 

x = 30/10 = 3

 

and that's the answer.  The beauty of this approach is that it is completely independent of the base of the logarithm.