Ask your own question, for FREE!
Mathematics 5 Online
OpenStudy (anonymous):

solve the following log equation question below

OpenStudy (anonymous):

\[\log_{3}x+\log_{3}(x-8)=2 \]

OpenStudy (phi):

the first step is use the rule \[ \log(a)+\log(b)= \log(a\cdot b) \] in other words, you can replace the addition of two logs (of the same base) with one log, where you multiply. can you do that ?

OpenStudy (anonymous):

yea i got that so far

OpenStudy (phi):

what do you have so far ?

OpenStudy (anonymous):

x^2-8x inside log

OpenStudy (phi):

\[ \log_3(x^2-8x) = 2\] make each side the exponent of the base 3: \[ 3^{\log_3(x^2-8x)} = 3^2\] and use the rule \[ a^{log_a(b)} = b \] to simplify the left side. in other words, 3 to the power log base 3 "undoes" the log

OpenStudy (anonymous):

do you end up with just x^2-8x=9

OpenStudy (phi):

yes

OpenStudy (anonymous):

ok cool then factor and x=-1 cant be in the solution so its just 9

OpenStudy (phi):

yes

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Latest Questions
Arriyanalol: i need help
18 hours ago 7 Replies 1 Medal
Arriyanalol: CONGRATS to me
21 hours ago 8 Replies 2 Medals
Legomaster346: What colleges are good that are near Arab Alabama?
1 week ago 5 Replies 0 Medals
Arriyanalol: i need help
1 week ago 6 Replies 2 Medals
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!