f(x) = x³ - 8x² + 22x - 20
given x = a, x = b are zeros of a polynomial then
(x - a) and (x - b) are factors and the polynomial is the product of the factors
f(x) = k(x - a)(x - b) → ( k is a multiplier )
note that complex zeros occur in conjugate pairs
3 + 1 is a zero then 3 - i is a zero
zeros are x = 2, x = 3 + i and x = 3 - i, thus
(x - 2 ),(x - (3 + i )) and (x - (3 - i )) are the factors
f(x) = (x - 2)(x - 3 - i )(x - 3 + i)
= (x - 2)(x² - 6x + 10)
= x³ - 8x² + 22x - 20
