SOLUTION: logx+log(x+21)=2

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Question 804824: logx+log(x+21)=2
Found 2 solutions by erica65404, Alan3354:
Answer by erica65404(394)   (Show Source): You can put this solution on YOUR website!
when you add logs together it is the same as multiplying the numbers u are logging.
example:
loga+logb=log(ab)
You need to do this to this problem


when log doesn't have a number where the base should be, it means the base is zero.
turn this into an exponential equation.



Now factor the equation.

x= 25, -4

Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
logx+log(x+21)=2



(x+25)*(x-4) = 0
x = 4
================
You can't use x = -25, log(-25) is not allowed

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