In my textbook, there's an equation with log

ex.
log(50,000)+log(150,000)= some number

But when I use the log button on the calculator, the answer is not correct? But when I use the ln button, it's the correct answer?

So for log, you press ln, then what is the log button on the calculator for?

2 answers

It is not clear to me above what is the base of the log. Unstated, we often use base 10, but not always. I am not certain what you are doing. But the point of the above is something else..

log Y + log x= log (x*Y)
so log(5*1.5*10^9)=9log(7.5)
the equation in my book is

0.5log(50,000)+0.5log(150,000)=11.37

I just punch these numbers and using log button on my calculator, the answer isn't correct. But when i use ln instead of log on my calculator, the answer is correct.