If a polynomial function f of x has roots negative 8 , 1 , and 6 i , what must also be a root of f of x ?

For a polynomial with real coefficients, any nonreal complex roots occur in conjugate pairs. Since 6i is a root, its complex conjugate, −6i, must also be a root. Therefore, the correct choice is negative 6i.

AI-written and checked against the verified answer.