SOLUTION: ((( x^4 -x^2 -12 = 0)))) Can you please help me with this problems

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Question 32359: ((( x^4 -x^2 -12 = 0)))) Can you please help me with this problems
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Solve:
x%5E4-x%5E2-12+=+0 Rewrite this as a quadratic equation by temporarily substituting y+=+x%5E2.
y%5E2-y-12+=+0 Solve by factoring.
%28y%2B3%29%28y-4%29+=+0 Apply the zero products principle.
y%2B3+=+0 and/or y-4+=+0
If y%2B3+=+0 then y+=+-3
If y-4+=+0 then y+=+4
But, y+=+x%5E2, so:
x%5E2+=+-3 Take the square root of both sides.
x+=+sqrt%283%29i and x+=+-sqrt%283%29i
x%5E2+=+4 Take the square root of both sides.
x+=+2 and x+=+-2
The four roots are:
x+=+sqrt%283%29i
x+=+-sqrt%283%29i
x+=+2
x+=+-2