SOLUTION: ln x-ln(x+7)=-1

Question 142208: ln x-ln(x+7)=-1
Found 2 solutions by jim_thompson5910, ankor@dixie-net.com:
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!

Start with the given equation

Combine the logs using the identity

Use the property ==> to rewrite the equation

Rewrite as

Cross Multiply

Subtract x from both sides

Factor out the GCF x

Divide both sides by

So our answer is which is approximately

Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
ln(x)- ln(x+7) = -1
:
Same as
ln() = -1
:
Find e^ of both sides
= .36788
:
Multiply both sides by (x+7) and you have:
x = .36788(x+7)
:
x = .36788x + 2.5752
:
x -.36788x = 2.5752
:
.63212x = 2.5752
x =
x = 4.074
:
:
Check solution on calc: enter ln(4.074) - ln(11.074) = -.99997 ~ -1
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