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Question:

Find all values of z such that z^4 - 4z^2 +3 = 0.

 

What I did:

z^2 = y

y^2 - 4y + 3 = 0

(y - 3)(y - 1) = 0

y = 3 ... y2 = 3 ... y = rt 3

y = 1 ... y^2 = 1 ... y = 1

 

Why is my answer wrong?

 


 

 Aug 31, 2020
edited by Guest  Aug 31, 2020
 #1
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Because z^4, your answers should read:

y = +or- sqrt(3), and

y = +or- 1

 Aug 31, 2020

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