Can someone please explain to me home to work this logarithmic equation, I have finals Monday!!!! Solve: 2 log3 (x+2)=log3 9+2
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OpenStudy (anonymous):
typo *how
OpenStudy (anonymous):
deja vu, that strange feeling you get when you think you have been there before
OpenStudy (anonymous):
I'm sorry lol I just don't get it
OpenStudy (anonymous):
\[2\log_3(x+2)=\log_3(9)+2\] and if it says in the problem
\[2\log_3(x+2)=\log_39+2\] it means the same thing
first thing we do is change
\[\log_39\] to 2 because
\[3^2=2\] is that part ok?
OpenStudy (anonymous):
O k.....
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OpenStudy (anonymous):
\[\log_b(x)=y\iff b^y=x\] so
\[\log_3(9)=2\iff 3^2=9\]
OpenStudy (anonymous):
okay got u
OpenStudy (anonymous):
so now we have
\[2\log_3(x+2)=2+2=4\] divide both sides by 2 to get
\[\log_3(x+2)=2\] so far so good?
OpenStudy (anonymous):
Where did the 2+2=4 come from?
OpenStudy (anonymous):
original problem had
\[\log_39+2\] on the right, and since
\[\log_39=2\] we get
\[\log_39+2=2+2=4\]
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OpenStudy (anonymous):
Okay
OpenStudy (anonymous):
now divide by 2 to get
\[\log_3(x+2)=2\]
OpenStudy (anonymous):
and rewrite in "equivalent exponential form" meaning change
\[\log_b(x)=y\text { to } b^y=x\] so turn this into
\[3^2=x+2\]
OpenStudy (anonymous):
then solve for x by subtracting 2 from both sides
OpenStudy (anonymous):
Okay thank you much :)
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