Question

solve for x:
log x+log(x-9)=log(20x)

Answer 1

\[\log x + \log(x-9)=\log(20x) \\
\log x+\log(x-9)=\log(20)+\log x\\
\log(x-9)=\log(20)\]

Answer 2

I hope the rest will be obvious :)

Answer 3

The second line, I just used the rule \(\log(ab)=\log(a)+\log(b)\) on log(20x)

Answer 4

would you bring the log(20) over and make it log[(x-9)/20] ?

Answer 5

Well since you have a log on both sides, you can just "cancel" them out and get x-9 = 20 :)

Answer 6

oh, i see. that makes sense. thank you! (:

Answer 7

yw :)