Question 199851
Remember  that  if  you  have  a  complex root,  you  also  have  the  congugate root.
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y= (x+3i)(x-3i) (x+4i)(x-4i)
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y = (x^2 -9i^2) (x^2 -16i^2),,,,with  i^2 =(-1)
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y = (x^2 +9) ( x^2 +16)
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y= x^4 +25x^2 + 144
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