Question 818956
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Hi
find a quadratic equation whose solutions are +2i and -2i
The factor theorem states that a polynomial f(x) has a factor (x &#8722; k) if and only if f(k) = 0. 
 f(x) = (x+2i)(x-2i) = x^2 + 4    |note  i^2 = -1
Check answer with FOIL
F	First terms    x^2
O	Outside terms  -2i
I	Inside terms   +2i
L	Last terms    -4(-1)