Question 824419
 	Find all zeros of the function and write the polynomial as a product of linear factors.

f(x) = x^4 + 13x^2 + 36
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Sub for x^2, eg u, then it's a quadratic
{{{u^2 + 13u + 36 = 0}}}
Solve for u.
Sub x^2 for u.
Solve for x (4 solutions).