Question

I really could use some HELP if anyone would PLEASE take a look at this.
Use the zero to find the remaining zeros of the function. f(x) = x^3 - 7x^2 + 4x - 28; zero: 2i

Answer 1

well the zero 2i will have a conjugate pair -2i

so (x -2i)(x + 2i) should be a factor

or x^2 + 4 is a factor.

you could use a little polynomial division or synthetic division to find the other zero...


hope this helps

Answer 2

or a little intuition may help...

(x^2 + 4)(x + a) and the product of 4 and a must be -28...

saves division

Answer 3

This is better:
Sum of roots: 2i x 2i x X=7. and solve simulataenously with product of roots.

Answer 4

thank you I am new to this site and did not look here for any possible answers. Thank you so very much.