Turn on thread page Beta
    • Political Ambassador
    • Thread Starter
    Offline

    20
    ReputationRep:
    Political Ambassador
    i got 2 questions that im stuck on, please tell me the method, i can use that then to find the answer. put the answer in the spoiler if u want so i can compare perhaps

    Factorise 2x^2 - 11xy + 5y^2

    i've never came across this type before

    and also

    simplify expression, leave answer in factorised form

    x^2 + 4x + 3
    ----------------
    x + 1

    thank you!
    Offline

    13
    ReputationRep:
    (Original post by ihatePE)
    i got 2 questions that im stuck on, please tell me the method, i can use that then to find the answer. put the answer in the spoiler if u want so i can compare perhaps

    Factorise 2x^2 - 11y + 5y^2

    i've never came across this type before

    and also

    simplify expression, leave answer in factorised form

    x^2 + 4x + 3
    ----------------
    x + 1

    thank you!
    For the first don't be thrown off by the y's. Just go about it like an ordinary quadratic. Not really sure how other to explain this than by an example. Consider x^2 + 2xy + y^2. We are just going to treat it as a normal quadratic and so we want to find two numbers which multiply to give y^2 and sum to give 2y. y and y satisfy this. Hence x^2 + 2xy + y^2 = (x+y)(x+y) = (x+y)^2. Now try it with your's.


    For the second, assuming it is meant to be \frac{x^2 + 4x + 3}{x+1} then factorise the numerator.
    • Political Ambassador
    • Thread Starter
    Offline

    20
    ReputationRep:
    Political Ambassador
    (Original post by 16Characters....)
    For the first don't be thrown off by the y's. Just go about it like an ordinary quadratic. Not really sure how other to explain this than by an example. Consider x^2 + 2y + y^2. We are just going to treat it as a normal quadratic and so we want to find two numbers which multiply to give y^2 and sum to give 2y. y and y satisfy this. Hence x^2 + 2y + y^2 = (x+y)(x+y) = (x+y)^2. Now try it with your's.


    For the second, assuming it is meant to be \frac{x^2 + 4x + 3}{x+1} then factorise the numerator.
    sooo sorry, i meant 11xy but other than that i understand your explanation thank you
    Offline

    13
    ReputationRep:
    (Original post by ihatePE)
    sooo sorry, i meant 11xy but other than that i understand your explanation thank you
    It's OK, I meant 2xy in my example too whoops.
    Offline

    2
    ReputationRep:
    (Original post by ihatePE)
    sooo sorry, i meant 11xy but other than that i understand your explanation thank you
    (2x-y)(x-5y)

    use AC method
    • Political Ambassador
    • Thread Starter
    Offline

    20
    ReputationRep:
    Political Ambassador
    (Original post by under8ed)
    (2x-y)(x-5y)

    use AC method
    what is AC method?
    Offline

    2
    ReputationRep:
    (Original post by ihatePE)
    what is AC method?
    The method you use to solve quadratics, i suspect you do this without realising

    https://people.richland.edu/james/misc/acmeth.html

    This simplifies it, take the 'a' to equal 2 and the 'c' to equal 5
    Offline

    18
    ReputationRep:
    (Original post by 16Characters....)
    It'is OK, I meant 2xy in my example too whoops.
    Attachment 507219507221

    Hope this helps slightly, not sure if it's the AC method but it's what I do.
    Attached Images
      
    Offline

    13
    ReputationRep:
    (Original post by ScienceFantatic)
    Attachment 507219507221

    Hope this helps slightly, not sure if it's the AC method but it's what I do.
    I know how to factorise a quadratic, I do not however know how to proofread. You may wish to quote the OP here instead of me...

    Edit: Though thank you for trying to help out.
    Offline

    18
    ReputationRep:
    (Original post by 16Characters....)
    I know how to factorise a quadratic, I do not however know how to proofread. You may wish to quote the OP here instead of me...

    Edit: Though thank you for trying to help out.
    You're right I did quote the wrong person, sorry!

    ihatePE
    • Political Ambassador
    • Thread Starter
    Offline

    20
    ReputationRep:
    Political Ambassador
    (Original post by ScienceFantatic)
    You're right I did quote the wrong person, sorry!

    ihatePE
    oh thanks! i'll use this for other questions i have now
    Offline

    19
    ReputationRep:
    (Original post by under8ed)
    (2x-y)(x-5y)

    use AC method
    ??
    Offline

    2
    ReputationRep:
    (Original post by TeeEm)
    ??
    I didnt realise other people arent taught this, its just a logical way of solving a quadratic
    Offline

    19
    ReputationRep:
    (Original post by under8ed)
    I didnt realise other people arent taught this, its just a logical way of solving a quadratic
    What school year are you in?
    Offline

    14
    ReputationRep:
    (Original post by ihatePE)
    i got 2 questions that im stuck on, please tell me the method, i can use that then to find the answer. put the answer in the spoiler if u want so i can compare perhaps

    Factorise 2x^2 - 11xy + 5y^2

    i've never came across this type before

    and also

    simplify expression, leave answer in factorised form

    x^2 + 4x + 3
    ----------------
    x + 1

    thank you!
    If you can't see it intuitively maybe then set  y = c (c is a constant) and notice (hopefully) how this can be factorised in the normal way
    Offline

    2
    ReputationRep:
    (Original post by TeeEm)
    What school year are you in?
    yr 11
    Offline

    19
    ReputationRep:
    (Original post by under8ed)
    yr 11
    No worries ... some teachers teach some very exotic approaches
    For most students which take maths beyond GCSE, factorizing a quadratic requires no particular method.

    All the best!
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: February 24, 2016

University open days

  1. Loughborough University
    General Open Day Undergraduate
    Fri, 21 Sep '18
  2. University of Cambridge
    Churchill College Undergraduate
    Fri, 21 Sep '18
  3. Richmond, The American International University in London
    Undergraduate Open Day Undergraduate
    Fri, 21 Sep '18
Poll
Which accompaniment is best?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.