Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    4
    ReputationRep:
    I got asked to research this question for homework but I have absolutely no clue:

    Prove that if (x-p) is a factor of f(x) then f(p) = 0

    Thanks in advance for any help
    Offline

    6
    ReputationRep:
    (Original post by OldSkoolCanary)
    I got asked to research this question for homework but I have absolutely no clue:

    Prove that if (x-p) is a factor of f(x) then f(p) = 0

    Thanks in advance for any help
    Is f(x) a polynomial? It doesn't matter too much, but that's usually the context of these kinds of questions.

    Anyway, (x - p) is a factor so you can write: f(x) = (x - p)q(x), for some other function q. What can you say about f(p) now?
    • Thread Starter
    Offline

    4
    ReputationRep:
    (Original post by aMathsDude)
    Is f(x) a polynomial? It doesn't matter too much, but that's usually the context of these kinds of questions.

    Anyway, (x - p) is a factor so you can write: f(x) = (x - p)q(x), for some other function q. What can you say about f(p) now?
    I’m not sure, f(p)=f(x)/q(x)? Sorry we’ve only just started this content so I’m not very confident on it
    Offline

    6
    ReputationRep:
    (Original post by OldSkoolCanary)
    I’m not sure, f(p)=f(x)/q(x)? Sorry we’ve only just started this content so I’m not very confident on it
    Not quite: We have f(x) = (x - p)q(x). So just plug in p to both sides. What is (x - p) when x = p?
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • What newspaper do you read/prefer?
    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
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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

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