Give an expression for f(x) with leading coefficient 2, of degree 3, and having roots x = -6, x = 2 - 3i, and x = 2 + 3i. Your final answer should not contain any i's.
a) f(x) = 2(x + 6)(x - 2)²
b) f(x) = 2(x + 6)(x² - 4x + 13)
c) f(x) = 2(x + 6)(x² - 4x + 4)
d) f(x) = 2(x + 6)(x² - 4x + 5)