Question

Determine the factors of x2 − 8x − 12.

(x − 6)(x + 2)

(x + 3)(x − 4)

Prime

(x + 6)(x − 2)

Answer 1

Find two numbers that multiply to make your constant and add to make the coefficient of x

Answer 2

i think is is C

Answer 3

actually... none of those options seem to work... unless I dont know what im talking about anymore..

Answer 4

it does not have integral factors

Answer 5

because b^2 -4ac is not a perfect square

Answer 6

/;gt\

Answer 7

you can safely choose prime here....but it has irrational factors

Answer 8

so just for this question because of multiple choice, it would be prime, but it does have irrational factors..ha i should have known

Answer 9

now wonder i was confused okay :P

Answer 10

x = 8 +/- sqrt (108) /2

Answer 11

when
b^2-4ac is perfect square ----> integer roots
b^2-4ac is positive ----->real roots
b^2 -4ac is negative ---->imaginary roots --->prime

Answer 12

here, if domain of x is integer, only then we can consider it as prime

Answer 13

ahh okay then :)

Answer 14

very thorough explanation

Answer 15

) thanks!
i hope harlie got it ...

Answer 16

Actually, I think the definition of a "prime polynomial" is when it cannot be factored into the product of two polynomials, using integer values. It doesn't mean that it "can't be written as a product" because any trinomial can, with rational, irrational or complex roots. :)

Answer 17

Nnope i still dont get it

Answer 18

which part ?

Answer 19

the one u said

Answer 20

you know what are a,b, c ?

Answer 21

is the answer A

Answer 22

Did you check A by doing the FOIL multiplication, to see if you get back the original polynomial?

Answer 23

You can check each answer by multiplying (one of the shortcomings of this kind of questions being multiple choice, since that doesn't teach you a darn thing about how to factor the polynomial).

But as @hartnn points out, the RIGOROUS way to show that it does not factor is to calculate the discriminant. He told you above what that tells you about the roots (and hence, the ability to factor).

Answer 24

I am not sure its because i only have 3 days to finish what i am doing so i need to know what is the answer

Answer 25

Do you know how to FOIL multiply?

Answer 26

(x − 6)(x + 2) = ???

Answer 27

x2 − 8x − 12.

Answer 28

How did you get that? show me each of F-O-I-L steps.

Answer 29

Meaning, show all 4 terms.

Answer 30

i didn't i just guessed

Answer 31

Well, therein lies the problem. :) You aren't supposed to guess. Clearly, whatever the class is that you're in, this is material that you are expected to know. So if you don't learn how to do it, you will only get more and more behind.

FOIL mutliplication, remember this?

Answer 32

So you get

(x)(x) + 2(x)-6(x) -6(2)

Answer 33

is it B

Answer 34

Did you FOIL b to see if you get back to the original polynomial?

Answer 35

(x + 3)(x − 4) = ?

Answer 36

idk

Answer 37

Did you look at my example above on how to FOIL?

(x + 3)(x − 4) = x(x) -4(x) +3(x) -4(3) = ??

Answer 38

If you don't remember how to FOIL multiply, then you really need to review that before you go any further. You are not prepared to do factoring problems, if you don't understand multiplying first.

Answer 39

i know how to use the FOIL METHOD

Answer 40

You can review it here:
http://www.coolmath.com/algebra/03-polynomials/06-polynomials-multiplying-foil-01.htm

Answer 41

Ok, that's good. Then why, when I asked:

(x + 3)(x − 4) = ?

Did you say "IDK"? Just FOIL it. :)

Answer 42

x2 − 8x − 12.

Answer 43

No. Your middle term is wrong.

Answer 44

(x + 3)(x − 4) = x(x) -4(x) +3(x) -4(3) = ??

-4(x) +3(x)\(\neq\)-8x

Answer 45

so it the last one

Answer 46

Did you FOIL (x + 6)(x − 2) to check?

Answer 47

(x + 6)(x − 2) = ??

Answer 48

You need to know how to FOIL. IT'S IMPORTANT and if you don't, you will only be more and more lost when you get to the next topic. It's clear from the fact that you are being asked this problem that you are expected to know how to FOIL two binomials, and then how to factor ("un-FOIL") a trinomial. You can get this assignment turned in with every problem correct, but if you don't understand these basic concepts, you'll just be back here even more lost when you have to reduce a rational expression or find its domain, because you don't understand factoring a trinomial.

Answer 49

The answer prime

Answer 50

Well, if you've checked the other 3 by correctly FOIL'ing them, and none of them work, then that would be all that's left.