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9^x+1 +3^2x+1=36. Solve fo x

Boniface  Feb 25, 2017
 #1
avatar+87301 
+5

9^(x+1) + 3^(2x+1)= 36

 

9^x * 9  + 3*3^(2x) = 36      divide by 3

 

3 * 9^x  + 3^(2x)  = 12

 

3 * 9^x + (3^2)^x  = 12

 

3 * 9^x + 9^x   =  12

 

9^x * (3 + 1)   = 12

 

9^x * 4   = 12      divide by 4

 

9^x  =   3

 

[3^2]^x  = 3^1

 

3^(2x)  = 3^1     equate exponents

 

2x  =  1    →  x  = 1/2

 

 

cool cool cool

CPhill  Feb 25, 2017

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