SOLUTION: if 2^a=3 then 8^a=?

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Question 536039: if 2^a=3 then 8^a=?
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
  
2%5Ea = 3

Cube both sides:

%282%5Ea%29%5E3 = 3%5E3

Use the rule of exponents %28X%5EY%29%5EZ = X%5E%28YZ%29 and replace 3³ by 27

2%5E%283a%29 = 27

Use that same rule of exponents in reverse: X%5E%28YZ%29 = %28X%5EY%29%5EZ
 
%282%5E3%29%5Ea = 27

Replace 2³ by 8

8%5Ea = 27

Edwin