Question

What are the possible rational zeros of f(x) = 2x3 - 4x2 - 7x + 14?

Answer 1

a) 1/2, 1, 2 , 7/2, 7, 14
b) ± 1, ± 2, ± 7, ± 14
c) ± 1/2, ± 1, ± 2, ± 7/2, ± 7, ± 14
d) 1, 2, 7, 14

i got the answer for c? i'm not sure if it's correct.

Answer 2

How did you obtain (c) as your answer? What steps did you take to get there?

Answer 3

to be honest, i'm not really sure what i did.

Answer 4

Ok. fair' nuff. :)

You want to use the rational root theorem here. http://www.purplemath.com/modules/rtnlroot.htm is a very good set of notes (I'd recommend bookmarking it).

Here's the general list you should make when solving a problem like this:

f(x) = 2x^3 - 4x^2 - 7x + 14

Constant term = 14
Factors of 14 = 1, 2, 7, 14

Highest power of x is 3.
Coefficient of x^3 is 2
Factors of 2 = 1,2

Now the rest should follow from the rational root theorem.

Answer 5

okay thank you!