SOLUTION: 4. What is the solution of {{{log(3,(x + 7))}}} + {{{log(3, 3) = 2}}}? My choices are: -4 <--- I think it's this one but I'm not for sure... 5

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: 4. What is the solution of {{{log(3,(x + 7))}}} + {{{log(3, 3) = 2}}}? My choices are: -4 <--- I think it's this one but I'm not for sure... 5       Log On


   

Question 837883: 4. What is the solution of log%283%2C%28x+%2B+7%29%29 + log%283%2C+3%29+=+2?
My choices are: -4 <--- I think it's this one but I'm not for sure...
5
10
no solution
This is what I did: First I wrote it a single logarithm. To do that I multiplied (x + 7) and 3 to get: log+%283%2C%283x+%2B+21%29%29. Then I converted it to exponential form: 3%5E2=3x+%2B+21. 3 to the power of 3 is 9, then I just solved from there. 9 - 21=-12 and then -12/3=-4. But after inputting -4 into the original equation for x, I don't come up with 2 on both sides. Does that mean they aren't equal?
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
What is the solution of log%283%2C%28x+%2B+7%29%29 + log%283%2C+3%29+=+2?
Your answer of x=-4 is correct.
check:
log%283%2C%28x%2B7%29%29=log%283%2C%28-4%2B7%29%29=log%283%2C%283%29%29=1
log%283%2C%283%29%29=1
note: log of base always=1