Question 1079208
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<pre>
{{{x^4 + 13x^2 + 36}}} = (apply factoring) = {{{(x^2+4)*(x^2+9)}}}.

The zeroes for {{{x^2+4}}} are the complex numbers 2i and -2i.

The zeroes for {{{x^2+9}}} are the complex numbers 3i and -3i.


The full set of zeroes is {-3i, -2i, 2i, 3i}.
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Solved.