SOLUTION: I need to find all the imaginary solutions of the equation by factoring. x^4+14x^2-32=0 I can not get this problem, please help

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Question 396457: I need to find all the imaginary solutions of the equation by factoring.
x^4+14x^2-32=0
I can not get this problem, please help
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
Letting u+=+x%5E2,

u%5E2+%2B+14u+-+32+=+0

%28u%2B16%29%28u-2%29+=+0

u = -16 or u = 2

Taking positive and negative square roots of both values for u, we get

x = 4i, -4i, sqrt%282%29, -sqrt%282%29.

The imaginary roots are 4i and -4i.