Have a test tomorrow, worksheet has a few questions we haven't gone over and I know my teacher will put them on there, because she always does that:

Question

vuriffy · Answer

$$\log_{10}(x+9)=2+\log_{10}x  $$

vuriffy · Answer

Solve.

vuriffy · Answer

I am still unsure on how to start it.

hayhayz · Answer

just subtract

hayhayz · Answer

log_10(x+9)-log_10(x) =2
so
log_10((x+9)/x) = 2
(x+9)/x = 10^2
x+9=100x
x=9/99
   =1/11

vuriffy · Answer

So, you turn it around to equal the whole number?

hayhayz · Answer

remmber that
log(x) + log(y) = log(x*y)
and
log(x)-log(y)=log(x/y)
the basic log rules

hayhayz · Answer

you can try to prove these identities to yourself, it will make you more comfortable with it

vuriffy · Answer

I understand it now, thank you. I just didn't know how to start it. 
I have two more, if you don't mind helping me with them. I can tag you.

hayhayz · Answer

sure :)