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# factoring help watch

1. How would I solve this by factorizing? It's proving to be rather difficult for me
2. (Original post by upthegunners)

How would I solve this by factorizing? It's proving to be rather difficult for me
Kinda hard given no other information i.e. factors, try common results f(-1) f(-2) and f(2) into the bracketed equation, one of them may sum 0, if not keep trying, its hard with the amount of info you have
You need a value of t such that
3. (Original post by Robbie242)
Kinda hard given no other information i.e. factors, try common results f(-1) f(-2) and f(2) into the bracketed equation, one of them may sum 0, if not keep trying, its hard with the amount of info you have
The mark scheme solve it by factoring. Not using the reminder theorem.

In addition, this is from an M1 paper

Pretty horrible to have to work with.
4. It's really just a quadratic equation.
5. (Original post by upthegunners)

How would I solve this by factorizing? It's proving to be rather difficult for me
wrong section!
6. (Original post by Robbie242)
Kinda hard given no other information i.e. factors, try common results f(-1) f(-2) and f(2) into the bracketed equation, one of them may sum 0, if not keep trying, its hard with the amount of info you have
You need a value of t such that
Why would I need a value such that ??
7. (Original post by upthegunners)
Why would I need a value such that ??
Because if something sums 0, it is a factor e.g. the equation 2x^3-x^2-1=0
f(1)=2(1)^3-(1)^2-1=0 therefore (x-1) is a factor, similarly here, you need one part to equal 15 and that combines with the -15 to make 0, which is one of the roots needed
8. Use A=t^2, so you get 3A^2-4A-15=0, which can be solved much more easily. When you're done factorising, put t^2 back in for A and you'll have your factorised polynomial.
9. (Original post by uttamo)
Use A=t^2, so you get 3A^2-4A-15=0, which can be solved much more easily. When you're done factorising, put t^2 back in for A and you'll have your factorised polynomial.
Ah great method, better then random guessing!
10. (Original post by upthegunners)

How would I solve this by factorizing? It's proving to be rather difficult for me
say that
11. (Original post by upthegunners)
Why would I need a value such that ??
Actually from the bracket, you can take out a quadratic factor to solve for t so
so a=3 b=-4 c=-15 don't forget to square root afterwards
12. I got to 3t^4-9T^2+5t^2-15

3t^2(t^2-3)+5(t^2-3)
(3t^2+5)(t^2-3)

t= root(-5/3), root(3)

you just simply treat it as a quadratic as long as they are in the difference of

2,1,0 your fine so you can factorise t^10+t^5+5 (example)
13. (Original post by yaboy)
I got to 3t^4-9T^2+5t^2-15

3t^2(t^2-3)+5(t^2-3)
(3t^2+5)(t^2-3)

t= root(-5/3), root(3)

you just simply treat it as a quadratic as long as they are in the difference of

2,1,0 your fine so you can factorise t^10+t^5+5 (example)
EDIT: nvm lol me being stupid...
14. (Original post by Albino)
EDIT: nvm lol me being stupid...
I think so because you need -9 and +5 otherwise you dont get the -4 required.
15. (Original post by yaboy)
I think so because you need -9 and +5 otherwise you dont get the -4 required.
i got my equation as

edited
16. (Original post by Albino)
i got my equation as
how on earth did you get -5? that means you must of got +9T^2-5t^2 which is wrong.
17. (Original post by yaboy)
how on earth did you get -5? that means you must of got +9T^2-5t^2 which is wrong.
I need to learn how to read
18. (Original post by Albino)
I need to learn how to read
You would get tortured if you did that north korea

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