SOLUTION: solve the equation log2(x+2)+log2(x-4)=4 Thanks, Nikky

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Question 472890: solve the equation
log2(x+2)+log2(x-4)=4
Thanks,
Nikky
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
solve the equation
log2(x+2) + log2(x-4) = 4
Same as:
log2%28%28x%2B2%29%2A%28x-4%29%29 = 4
FOIL
log2%28x%5E2-2x-8%29 = 4
exponent equiv of logs
x^2 - 2x - 8 = 2^4
:
x^2 - 2x - 8 = 16
:
x^2 - 2x - 8 - 16 = 0
:
x^2 - 2x - 24 = 0
Factors to
(x-6)(x+4) = 0
Two solutions
x = 6
x = -4
:
x = 6 is the only solution to the original equation (can't have the log of a neg)