N=4 i and 2i are zeros f(-2)=40

Answer 1

f(x) = a(x - i)(x + i)(x - 2i)(x + 2i)

f(x) = a(x² + 1)(x² + 4)

f(-2) = 40

40 = a(4 + 1)(4 + 4)

40 = 80a

1/2 = a

f(x) = (1/2)(x² + 1)(x² + 4)