Question

For the following function, one zero is given. Find all the others

Answer 1

Answer:

4 - i, 4 + i, 2.

Step-by-step explanation:

Complex zeros exist as conjugate pairs so another zero is  4 + i.

So one factor of f(x) is

(x - (4 + i))(x - (4 - i))

= (x - 4 - i)(x - 4 + i)

= x^2  - 4x + ix - 4x + 16 - 4i  - ix + 4i  - i^2

= x^2 - 8x + 16 - (-1)

= x^2 - 8x + 17

Dividing:

x^2 - 8x + 17 ) x3 - 10x2 + 33x - 34( x - 2

                        x3 - 8x^2 + 17x

                               -2x^2 + 16x - 34

                                -2x^2 + 16x - 34

So the third root is 2:

x - 2 = 0

x = 2.