SOLUTION: How do you solve logx+log(x-21)=2

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Question 968826: How do you solve logx+log(x-21)=2
Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
logx +log(x-21) = 2
use log rule log(xy) = log(x) + log(y)
log (x^2 -21x) = 2
use definition of log
x^2 -21x = 10^2
x^2 -21x -100 = 0
factor equation
(x-25)*(x+4) = 0
x = 25 or -4