Question

How do I solve a logarithmic equation?
For example, log2 (x+4) + log2 (x) = 5.

Answer 1

is that log base 2 ???

Answer 2

or log base 10 ???

Answer 3

Yes. I haven't gotten the hang of the controls yet.

Answer 4

???

Answer 5

i will bet base 2

Answer 6

is this the problem: \(\large log_2(x+4)+log_2(x)=5 \)

or is it: \(\large log2(x+4)+log2(x)=5 \)

Answer 7

It is the former.

Answer 8

@satellite73 ... ding, ding, ding, ding!!!

Answer 9

ok... do you know this rule for logs: \(\large log_bM+log_bN=log_b(M\cdot N) \) ???

Answer 10

Yes, I do. So I use that rule and then what do I do?
I think I know the answer but I could use a refresher.

Answer 11

so you can apply that to the left side of the equation to get :
\(\huge log_2[x(x+4)]=5 \)

we good so far?

Answer 12

Yes. I understand. So then I expand x(x+4)?

Answer 13

yes... but you can do that later...

Answer 14

do you know how to write this logarithmic equation in exponential form:

\(\large log_{10}(1000)=3 \) ???

Answer 15

10 ^ 3 = 1000. Yes. So I write the equation in exponential form?

Answer 16

yes.... :)

Answer 17

wat equation u got now?