SOLUTION: I do not have a very large understanding of logarithms, and i can't solve the question: log 7 + log x = 2 (The answer is 100/7) I can solve things such as log x

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Question 309381: I do not have a very large understanding of logarithms, and i can't solve the question:
log 7 + log x = 2
(The answer is 100/7)
I can solve things such as log x - log 6 = log 15 without having to worry about the base 10, but i do not understand when i need to use it to get the right answer.
Found 2 solutions by CharlesG2, Earlsdon:
Answer by CharlesG2(834) (Show Source):
You can put this solution on YOUR website!
"I do not have a very large understanding of logarithms, and i can't solve the question:
log 7 + log x = 2
(The answer is 100/7)
I can solve things such as log x - log 6 = log 15 without having to worry about the base 10, but i do not understand when i need to use it to get the right answer."
log 7 + log x = 2
means
log10 7 + log10 x = 2
the 10 is your base (b)
logarithmic rule: logb (mn) = logb (m) + logb (n)
so we have
log10 (7x) = 2
logarithmic rule: logb (y) = x is equivalent to b^x = y
so we have
10^2 = 7x
100 = 7x
100/7 = x
hope this helps

Answer by Earlsdon(6294) (Show Source):
You can put this solution on YOUR website!
Solve for x:
First, apply the "product rule" for logarithms:
Now write this in exponential form: --->
Divide both sides by 7.
S0...

SOLUTION: I do not have a very large understanding of logarithms, and i can't solve the question: log 7 + log x = 2 (The answer is 100/7) I can solve things such as log x - log 6 =