Join TSR now and get all your revision questions answeredSign up now

Solution of Equations Help

    • Thread Starter
    Offline

    0
    ReputationRep:
    I really need some help with this my teacher said I needed to complete a mini test for homework which we have one day to complete I've tried to search for ans answer but can find one can you please tell me the method to work this out and possibly the answer thanks.

    Question:
    Check if -3 and 3 are solutions of the equation of

    Please I really would like some help soon thanks.
    Offline

    2
    ReputationRep:
    that one is a lot simpler than you think.
    substitute each value to each side. lets say you wanted to know if 0 is a solution. put 0 on the left you get 0 cubed (0) and on the right root 40. 0 isnt root 40 so its not a solution.

    If the quesiton is worth like 1 mark or two literally write the equation but replace x with 3 (then after repeat with -3)

    for a 5 marker you compare values:
    3 cubed is 27, note that down
    root of 12x3+40 is root 76, 76 doesnt equal 27 therefore it's not a solution.

    -3 cubed is -27. root 12x-3 +40 is root 4 which is 2. 2 is not -27 so it's not a solution.
    TBH quite suprised it isnt asking you to actually find the solution, thats a lot more fun (and easy to do if you're not currently doing A level, then you do wierd stuff)
 
 
 
Poll
Which party will you be voting for in the General Election 2017?
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

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