Question

Use the factor theorem to match the polynomial with its factor.
x3 + x2 + 13x +4

Answer 1

you mean just factor?

Answer 2

these are the answer choices

x - 5
x+1
x -2
no factor listed for this polynomial
x+3

Answer 3

idk thats the question

Answer 4

factor theorem states that if (x-a) is af actor of a polynomial f(x) then f(a) = 0

Answer 5

im confused

Answer 6

so if x+3 is a factor , f(-3) = 0:
(-3)^3 + (-3)^2+ 13(-3) + 4 = -27 + 9 -39 + 4 not = 0, so x+3 is not a factor

Answer 7

where did you get the -3 from if it was a +3?

Answer 8

doesn't look like any of the list is a factor

Answer 9

no factor listed is the correct choice

Answer 10

so the answer is no factor listed for this poynomial?

Answer 11

yes

Answer 12

well wat about x^3 - 4x^2 - 4x - 5

Answer 13

because f(5), f(-1) and f(2) not = zero

Answer 14

the same answers go wit that one too

Answer 15

ah - that look more promising as there are negatives in it
try f(-1)
= -1 - 4 + 4 - 5 = 2 - so x+1 is not a factor

Answer 16

ohk so basically wat ur doing is plugging in the factors and see if they work??

Answer 17

i tried -3 and my answer was -8 is tht the rite answer?

Answer 18

well for example lets see if x - 5 is a factor - to do this we plug in x=5
f(5) = 125 - 4*25 - 4*5 - 5 = 125 - 100 - 20 -5 = 0
bingo!
(x - 5) is a factor

Answer 19

yes - 8 - so (x+3) is not a factor

Answer 20

you've got the idea now

Answer 21

ohk so im pluggin in the factors where the x's are and if it equals 0 with tht factor plugged in then it is a factor for tht polynomial and if i dnt get 0 then it is not a factor for tht polynomial? is tht rite?

Answer 22

yes - but remember for (x-a) plug in a , but for (x+a) you plug in -a

Answer 23

so for example, if f(5) = 0 then (x - 5) is a factor

Answer 24

ohk thanks