Hey there! Sign in to join this conversationNew here? Join for free

Help please on Quadratic Inequalities Watch

Announcements
    • Thread Starter
    Offline

    9
    ReputationRep:
    Use set notation to describe the set of values of x for which:
    2x^2-x-1<0 and 14<3x-2
    Answer is meant to be 'NO Values'???
    But I solved.. X =-0.5 and 1 and 16/3
    Any help would be much appreciated
    I'm confused
    Thank you
    • Study Helper
    Offline

    13
    (Original post by Musicanor)
    Use set notation to describe the set of values of x for which:
    2x^2-x-1<0 and 14<3x-2
    Answer is meant to be 'NO Values'???
    But I solved.. X =-0.5 and 1 and 16/3
    Any help would be much appreciated
    I'm confused
    Thank you
    Well neither of those two values satisfy the second inequality. Post your working if you'd like someone to check it.
    Offline

    0
    ReputationRep:
    You'll have to get a set of values that satisfy both inequalities. In your case the two you have mentioned above. You've already found out the values for 'X' to both equations; yet neither of them satisfy each other by not meeting certain conditions of being less or more some value for 'X' for each of them.

    For instance try to picture it on a number line and draw it out if you can...

    The first one is between the range '-0.5 < X < 1' where as the second one is 'X >16/3'

    Therefore by visualising these together on a single number line, you know there is no in-between area for then, hence there is no value for 'X' that satisfy both. Hope this makes more sense to you! Feel free to ask me again if I need to clarify anything else.
    • Thread Starter
    Offline

    9
    ReputationRep:
    (Original post by Chocolate beaver)
    You'll have to get a set of values that satisfy both inequalities. In your case the two you have mentioned above. You've already found out the values for 'X' to both equations; yet neither of them satisfy each other by not meeting certain conditions of being less or more some value for 'X' for each of them.

    For instance try to picture it on a number line and draw it out if you can...

    The first one is between the range '-0.5 < X < 1' where as the second one is 'X >16/3'

    Therefore by visualising these together on a single number line, you know there is no in-between area for then, hence there is no value for 'X' that satisfy both. Hope this makes more sense to you! Feel free to ask me again if I need to clarify anything else.
    Thank you this was really helpful
    • Thread Starter
    Offline

    9
    ReputationRep:
    (Original post by ghostwalker)
    Well neither of those two values satisfy the second inequality. Post your working if you'd like someone to check it.
    Thank you, this was really helpful
 
 
 
  • 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.

  • Poll
    Will you be richer or poorer than your parents?
    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.