Determine the zeros of f(x) = x^3 – 12x^2 + 28x – 9.

Question

wasiqss · Answer

find first zero by trial and error method

anonymous · Answer

x - 9 could be a factot or x - 3
using factor theorem
f(9) = 9^3 - 12(81) + 28(9) - 9 
using my calculator:

this = 0
so (x-9) is a factor and 9 is a zero

anonymous · Answer

to find the others
do long division or synthetic division

wasiqss · Answer

yes exactly

anonymous · Answer

or u can show me cus explaining thisgs to me doesnt help

anonymous · Answer

long division

          x^2  -  3x  + 1
         -----------------------
x - 9 ) x^3  -  12x^2  + 28x  - 9
           x^3  -    9x^2
           ------------
                     - 3 x^2  + 28x
                      - 3x^2   + 27x
                      -------------
                                        x - 9
                                        x - 9


quotient is  x^2 - 3x + 1

solve this to get the other zeros

anonymous · Answer

this wont factor so you need to use the quadratic formula