The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

This discussion is now closed.

Check out other Related discussions

Maths P1 help

I'm stuck with the final part of the question - finding the third factor. I'm sure it's pretty simple - I just can't work out what to do...
q19.jpg7.4KB
q19ans.jpg36.0KB
Reply 1
Avatar for k@tie
k@tie
10
RDoh
I'm stuck with the final part of the question - finding the third factor. I'm sure it's pretty simple - I just can't work out what to do...

if you multiply 2, -3 and ur final root, you'll get q.
Reply 2
Avatar for meepmeep
meepmeep
RDoh
I'm stuck with the final part of the question - finding the third factor. I'm sure it's pretty simple - I just can't work out what to do...

Divide through by (x-2)(x+3) and what you get is the last factor (x-a).
Reply 3
Avatar for lgs98jonee
lgs98jonee
2
(x-2)(x+3)=x^2+x-6
third factor is (x+a) there is 1x^3 so obviously only x

(x^2+x-6)(x+a)=x^3+ax^2+x^2+ax-6x-6a
=x^3+(1+a)x^2+(a-6)x-6a
equating coefficiants

-7=1+a
so a=-8

so third factor is x-8
p=-14
q=48 i think
Having found p and q, and hence your polynomial P(x), say that:
(x-2)(x+3)(x+a) = P(x), open up the left hand side and find a.
I think the suggested method is to do that factorial division thing, and divide (x-2) and (x+3) into your equation.
But I find it quicker and easier, and you might too, to just write out the equation, with your 2 factors underneath and kind of fill in the gaps.
Reply 6
Avatar for RDoh
RDoh
OP
Thanks - got it now :smile:
also for finding P and Q factor theorem is ten times quicker.

MB
actually ,u don't have to use long division to do this question.It just makes it more complicated, don't u think?
Reply 9
Avatar for adk
adk
Fong_Leonard
actually ,u don't have to use long division to do this question.It just makes it more complicated, don't u think?

yes it does.
You need to do long division for the second part (to factorise it).

MB
long division is not needed for the 2nd part as well
cos u have found the values of p and q .
just substitude the in the equation and then factorise it .as two os the zeroes have been given

personal view
Reply 12
Avatar for k@tie
k@tie
10
Just see my first comment, its way easier than doing long multplication!

Related discussions

Latest

Trending

Trending

Articles for you