Is X^2 - 16x + 63 prime? What is the factored version?

Question

Is X^2 - 16x + 63 prime?  What is the factored version?

anonymous · Answer

what is x equal to
???

anonymous · Answer

I don't know

karatechopper · Answer

Set up the parenthesis
(           ) (            )
Distribute x^2
(x         ) (x           )
Now you need to find factors of 63 that will add to be -16.
Can you name the factors of 63 for me please?

anonymous · Answer

umm, 1, 3, 7, 9, 21, 63?

karatechopper · Answer

Okay. Good don't forget the negative factors as well!!
-1, -3,- 7, -9, -21, -63

anonymous · Answer

(x -21  )(x-3  )

anonymous · Answer

I am not sure whether that is the correct answer

anonymous · Answer

does that mean it is prime?

anonymous · Answer

Yes it is prime.

anonymous · Answer

No it isn't

hartnn · Answer

not actually. 
from those factors, pick up 2 numbers whose sum is -16 and product = 63

anonymous · Answer

so its x^2 - 16x +63 = 63?

hartnn · Answer

what was that ? 
2 numbers from -1, -3,- 7, -9, -21, -63 that add up to -16 are ... ?

anonymous · Answer

-7, and -9

anonymous · Answer

( x-7)(x-9)
\

anonymous · Answer

I figured it out all of a sudden

karatechopper · Answer

Sorry, my wifi cut off..good to see the others stepped in to help..

hartnn · Answer

good, so you split -16x as -7x-9x
x^2 - 16x +63 = x^2 - 9x-7x +63
factor x from 1st 2 terms and -7 from last two terms, what u get ?

anonymous · Answer

I figured it out all of a sudden in my mind when I was doing something around the house

anonymous · Answer

( -7)(-9)=63
-7-9=-16

anonymous · Answer

now i'm totally lost.  Is -16 the factored value?  x = -16?

karatechopper · Answer

x shouldn't equal anything at the moment, you just needed to factor.

anonymous · Answer

(x-7)(x-9)    FOIL     First Outer Inner Last           Checking stage
x^2-9x-7x+63
x^2-16x+63

anonymous · Answer

x^2 is x squared

anonymous · Answer

so it is prime?

anonymous · Answer

It is prime because it can be factored

anonymous · Answer

thanks!

hartnn · Answer

It is NOT prime because it can be factored

anonymous · Answer

https://www.khanacademy.org/math/trigonometry/polynomial_and_rational/quad_factoring/v/factoring-polynomials-1

anonymous · Answer

I meant not prime

anonymous · Answer

I typed in prime

anonymous · Answer

so what does x^2 - 16x +63 equal?

hartnn · Answer

you split -16x as -7x-9x
x^2 - 16x +63 = x^2 - 9x-7x +63
factor x from 1st 2 terms and -7 from last two terms, what u get ?

anonymous · Answer

If you let $x=1$ doesn't it end up being an even number?