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How does ((sqrt(64, 5)*2^-1/5)/sqrt(8))^-4 equal 4? I've tried so many methods and can't seem to arrive to that answer (yes, I have to show how I worked it out). Any help is greatly appreciated!

 Sep 20, 2015

Best Answer 

 #1
avatar+33661 
+5

Try it as follows:

 

Numerator 

sqrt(64,5) → sqrt(2*32,5) → sqrt(2,5)*sqrt(32,5) → sqrt(2,5)*sqrt(2^5,5) → sqrt(2,5)*2

 

sqrt(2,5) is 2^(1/5), so sqrt(64,5) → 2*2^(1/5)

 

Hence sqrt(64,5)*2^(-1/5) → 2*2^(1/5)*2^(-1/5) → 2

 

Denominator

sqrt(8) → (sqrt(2)*sqrt(4)) → 2*sqrt(2)

 

Numerator/Denominator → 1/sqrt(2)

 

Raise this to the power -4:   (1/sqrt(2))^-4 → sqrt(2)^4 → (sqrt(2)^2)^2 → 2^2 → 4

 Sep 20, 2015
 #1
avatar+33661 
+5
Best Answer

Try it as follows:

 

Numerator 

sqrt(64,5) → sqrt(2*32,5) → sqrt(2,5)*sqrt(32,5) → sqrt(2,5)*sqrt(2^5,5) → sqrt(2,5)*2

 

sqrt(2,5) is 2^(1/5), so sqrt(64,5) → 2*2^(1/5)

 

Hence sqrt(64,5)*2^(-1/5) → 2*2^(1/5)*2^(-1/5) → 2

 

Denominator

sqrt(8) → (sqrt(2)*sqrt(4)) → 2*sqrt(2)

 

Numerator/Denominator → 1/sqrt(2)

 

Raise this to the power -4:   (1/sqrt(2))^-4 → sqrt(2)^4 → (sqrt(2)^2)^2 → 2^2 → 4

Alan Sep 20, 2015

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