+0  
 
0
560
1
avatar+20 

log3(x) + log3(x-2)=1

 Mar 23, 2016
 #1
avatar+128566 
0

log3(x) + log3(x-2)= 1         (note   1 =  log3 [3] )

 

log3 [ (x) (x-2) ]  =  log3 [3]     

 

Since we have the same logs on both sides, we can forget the logs and solve this :

 

(x) (x - 2)  = 3     simplify

 

x^2 - 2x - 3  = 0     factor

 

(x - 3) ( x + 1)  = 0      and setting each factor to 0, we have that x = 3 or x = -1

 

Reject -1 since it produces the log of a negative number in the original equation

 

So, x = 3 is the only solution

 

 

 

cool cool cool

 Mar 23, 2016

6 Online Users

avatar
avatar
avatar