SOLUTION: what is the solution set for the 9x^4-8x^2-1=0

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Question 1045134: what is the solution set for the 9x^4-8x^2-1=0
Answer by ikleyn(52824) About Me  (Show Source):
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what is the solution set for the 9x^4-8x^2-1=0
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9x%5E4-8x%5E2-1 = 0.

Factor the left side

%289x%5E2%2B1%29%2A%28x%5E2-1%29 = 0.


The equation deploys in two independent equations


1.  9x%5E2%2B1 = 0.  It has no real solutions (it has complex solutions x%5B1%2C2%5D = +/-%281%2F3%29%2Ai, if you know complex numbers) 


2.  x%5E2-1 = 0.   It has two solutions  x = 1  and  x = -1.