Advanced Hard!!!! - XP Math - Forums

 XP Math - Forums Advanced Hard!!!!
 User Name Remember Me? Password
 Register Arcade Members List Mark Forums Read

 Thread Tools Display Modes
 05-19-2015 #1 Dragonballful23     Join Date: Dec 2011 Posts: 386 Hard!!!! Determine what x equals. 9^(x+2)=3^x __________________ 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
 05-20-2015 #2 eliseo   Join Date: May 2015 Posts: 5 It's infinity
05-22-2015   #3
Dragonballful23

Join Date: Dec 2011
Posts: 386

Quote:
 Originally Posted by eliseo It's infinity
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!
__________________
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

 06-09-2015 #4 coolbro   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!
06-09-2015   #5
MAS1

Join Date: Dec 2008
Posts: 249

Quote:
 Originally Posted by Dragonballful23 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!
You made a small mistake.
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

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is Off Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home Welcome     XP Math News     Off-Topic Discussion Mathematics     XP Math Games Worksheets     Homework Help     Problems Library     Math Challenges

All times are GMT -4. The time now is 07:55 AM.

 Contact Us - XP Math - Forums - Archive - Privacy Statement - Top