Question

Determine which polynomial has (x-9) as a factor.

A. x^2-6+9

B. x^2+16x+63

C. x^2+14x+45

D. x^2-12x+27

Answer 1

heeey

Answer 2

hi

Answer 3

gimme a sec

Answer 4

a is 3+x^2

Answer 5

b is x^2+16x+63

Answer 6

@Mumustar78612 what does that mean?
+x^2 is not a factor or relevant to this question

@sunrise14 do oyu want ot know how to do this?

Answer 7

yes please

Answer 8

ok so you know that we are looking for 2 factors that make the original equation

AND you know that 1 of those factors is (x-9)

OK so far?

Answer 9

yes

Answer 10

ok so

the x^2 term comes from multiplying th efirst two terms of the brackets together

and in this case it is 1*x^2

so the factors must be

(x-9) (x-a)

(so that x*x gives us x^2)

OK so far?

Answer 11

yes

Answer 12

hello?

Answer 13

ok

now look at the last term

it is -9 *x

so looking at the answers


for answer a, x would be -1 (to give +9)
for answer b, x would be -7 (to give +63)
for answer c, x would be -5 (to give +45)
for answer a=d, x would be -3 (to give +27)

so now you need to find which ofthose would work out to give the correct middle factor when you expand the brackets

Answer 14

so for


a (x-9)(x-1)
b (x-9)(x-7)
c (x-9)(x-5)
d (x-9)(x-3)

which one expands to give the full quadratic answer correctly?

Answer 15

I believe I would lean to c but MrNood is a human calculator

Answer 16

to be honest, i dont know

Answer 17

Well you can factor the same expression different ways. Do you know how to factor?

Answer 18

ok = I have written the possible factors for all the answers

We know these are the possible ones because the first term must be x (to give us x^2) and the last term must be as written to give us the constant)

SO
Multiply them all out using
FOIL method

and see which one turns out to be a correct result

Answer 19

i did it in a certain way that was on the video but im still confused

Answer 20

So for a

multiply this
(x-9)(x-1)

Answer 21

using foil?

Answer 22

yes

Answer 23

i get confused trying to do that, can you draw?

Answer 24

no

you need that as a core skill to do factorising

If you can't do it then you need to go back and learn it

I promise you - time spent learning that method NOW will be repaid many times in the course of your future studies