Question

Find a cubic polynomial function f  with real coefficients that has the given zeros and the given function value.

Zeros                                            Function Value

-1, 2 + i                                           f (2) = - 9

Answer 1

Step 1:

Zeros of cubic function are

Using complex conjugate root theorem is a zero of the polynomial function.

Apply the formula .

Step 2:

Function value is .

Substitute in .

.

Solution:

The cubic polynomial function is  .