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05192015  #1 
Join Date: Dec 2011
Posts: 386

Hard!!!!
Determine what x equals.
9^(x+2)=3^x
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Finally finished all my tests!!! I am ekko main now ^_^ (ign: supersaiyan2363) It's not how much time you have, it's how you use it. Ekko 
05202015  #2 
Join Date: May 2015
Posts: 5

It's infinity

05222015  #3 
Join Date: Dec 2011
Posts: 386

Here is how you solve. since 9^(x+2)=3^x, you can say 3^(2x+4)=3^x
Now, just like when you factor quadratic equations, take out the 3. 3x+4=x 2x=4 x=2!
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Finally finished all my tests!!! I am ekko main now ^_^ (ign: supersaiyan2363) It's not how much time you have, it's how you use it. Ekko 
06092015  #4 
Join Date: Feb 2015
Posts: 1

Now, just like when you factor quadratic equations, take out the 3.
3x+4=x 2x=4 x=2! 
06092015  #5  
Join Date: Dec 2008
Posts: 249

Quote:
9^(x+2) = 3^x (3^2)^(x+2) = 3^x 3^(2(x+2)) = 3^x 3^(2x+4) = 3^x Since the base numbers are the same (3) then for the equation to be equal the exponents must be equal. 2x+4 = x 2x  x + 4 = x  x x + 4 = 0 x + 4  4 = 0  4 x = 4 Let's check our answer. 9^(4 + 2) = 3^(4) 9^(2) = 3^(4) 1/(9^2) = 1/(3^4) 1/81 = 1/81 

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