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# C1 Help =)? watch

1. Ok, This one has me confused

7.Take out a common factor first of all, and then factorise the quadratic factor:

(a) X^3 - x

(b) 2x^3 - 18x

If Someone could help me out by showing some working out that would be great!
2. Take out common factor

a) x(x^2-1)

b)2x(x^2-9)

Hope that helps.
3. Im assuming sketching graphs?

Think of it this way

x^3 - x common factor is x

so x(x^2-1)
Factorize x^-1 which is factorizing the quadratic factor

Its all in the question

Use the same method for (b)
4. (Original post by Shakaa)
Ok, This one has me confused

7.Take out a common factor first of all, and then factorise the quadratic factor:

(a) X^3 - x

(b) 2x^3 - 18x

If Someone could help me out by showing some working out that would be great!
I am not quite sure if you mean this but here it is:

a) x is common in both so:
x^3-x= x(x^2-1)

b) 2x is the common factor therefore:
2x^3-18x= 2x(x^2-9)

Hope this is what you were looking for
5. take out the common factor, in this example x

and then the next thing is to factorise it into a quadratic:

i.e. (x + a) (x + b)

in both the examples you have: b = -a

hope that helps!
6. (Original post by Aninja)
Take out common factor

a) x(x^2-1)

b)2x(x^2-9)

Hope that helps.
you haven't actually finished the second question there. Don't know if that was your intention or not..
7. (Original post by Nytram12)
you haven't actually finished the second question there. Don't know if that was your intention or not..
If I did that I would of given him the answer. He only asked for some working out. He can work out the rest, hopefully.
8. (Original post by Shakaa)
Ok, This one has me confused

7.Take out a common factor first of all, and then factorise the quadratic factor:

(a) X^3 - x

(b) 2x^3 - 18x

If Someone could help me out by showing some working out that would be great!
a) x^3 - x

=> x(x^2-1)
=> x(x+1)(x-1)

b)2x^3 - 18x

=> x(2x^2 -18)
=> x(2x + 6)(x-3)
9. (Original post by Shakaa)
Ok, This one has me confused

7.Take out a common factor first of all, and then factorise the quadratic factor:

(a) X^3 - x

(b) 2x^3 - 18x

If Someone could help me out by showing some working out that would be great!
a) Take out the common factor 'x' and factorise. You are left with You can factorise this using the difference of two squares

b) Again, take out the common factor 'x' and rewrite equation. You are left with a quadratic to factorise once more.
10. (Original post by gottastudy)
a) Take out the common factor 'x' and factorise. You are left with You can factorise this using the difference of two squares

b) Again, take out the common factor 'x' and rewrite equation. You are left with a quadratic to factorise once more.

Thanks for the help got sorted in the end, I was using the AC method to factorise instead of the AB >.<

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