Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    • Thread Starter
    Offline

    0
    ReputationRep:
    write down three values of x that satisfy the equation x(x-3)(2x+1)=0

    how do I do this?
    Offline

    11
    ReputationRep:
    (Original post by madfish)
    write down three values of x that satisfy the equation x(x-3)(2x+1)=0

    how do I do this?
    For the equation to equal zero, one of the three terms in the product must equal 0.
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by joostan)
    For the equation to equal zero, one of the three terms in the product must equal 0.
    so x= 0, 3, -1/2?
    • Political Ambassador
    Offline

    3
    ReputationRep:
    Political Ambassador
    (Original post by madfish)
    write down three values of x that satisfy the equation x(x-3)(2x+1)=0

    how do I do this?
    If

    a_1 \times a_2 \times a_3 \times ... \times a_n = 0

    then either the first, or the second, or the third..... or the nth term is zero.
    Offline

    11
    ReputationRep:
    (Original post by madfish)
    so x= 0, 3, -1/2?
    yes
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by Indeterminate)
    If

    a_1 \times a_2 \times a_3 \times ... \times a_n = 0

    then either the first, or the second, or the third..... or the nth term is zero.
    OKay I got the values of x but how do I do the next bit,.? it says: hence solve the inequality x(x-3)(2x+1) > 0
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by joostan)
    yes
    OKay I got the values of x but how do I do the next bit,.? it says: hence solve the inequality x(x-3)(2x+1) > 0
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by joostan)
    yes
    OKay I got the values of x but how do I do the next bit,.? it says: hence solve the inequality x(x-3)(2x+1) > 0
    Offline

    13
    ReputationRep:
    (Original post by madfish)
    OKay I got the values of x but how do I do the next bit,.? it says: hence solve the inequality x(x-3)(2x+1) > 0
    For what values is the function greater than 0?
    Attached Images
     
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by Felix Felicis)
    For what values is the function greater than 0?
    x>3, x>-0.5 x<0
    Offline

    13
    ReputationRep:
    (Original post by madfish)
    x>3, x>-0.5 x<0
    yes
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by Felix Felicis)
    yes
    how are you meant to do this?

    find a set of values of x for which both 6x-7<2x+3 and 2x^2-11x +5 >0
    Offline

    0
    ReputationRep:
    (Original post by madfish)
    how are you meant to do this?

    find a set of values of x for which both 6x-7<2x+3 and 2x^2-11x +5 >0
    remember for this kind of question always draw an inequality line.

    Work out x values for both equations first, then draw the inequality line for both equations and then you should see values of x which satisfiy both equations. (hope that makes sense)
    Offline

    13
    ReputationRep:
    Solve both inequalities and adjust the set of solutions accordingly
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by gaffer dean)
    remember for this kind of question always draw an inequality line.

    Work out x values for both equations first, then draw the inequality line for both equations and then you should see values of x which satisfiy both equations. (hope that makes sense)
    Thanks lad! One thing.. What's an equality line?
    Offline

    0
    ReputationRep:
    (Original post by madfish)
    Thanks lad! One thing.. What's an equality line?
    see this: http://www.sparknotes.com/math/algeb...section4.rhtml
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: March 23, 2013
Poll
Are you going to a festival?
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.