Turn on thread page Beta
    • Thread Starter
    Offline

    3
    ReputationRep:
    Can someone help solve this equation?

    10 - x = ( \sqrt 2 )x + 9

    = 10 minus x equals (square root of 2) times by x plus 9.

    Thanks,

    QUESTION SOLVED
    Offline

    4
    ReputationRep:
    i get the answer to be ; .

    Do you have an answer yourself?
    Offline

    19
    ReputationRep:
    You need to rearrange the equation so that you have only a multiple of x on one side and a number on the other. Try subtracting 9 from each side of the equation to start with; can you see what the next step would be?
    Offline

    2
    ReputationRep:
    I got x=1/(sqrt2 -1)
    Offline

    0
    ReputationRep:
    Take the 9 to one side and the x to the other.

    Factorise in x.

    Make x the subject.

    It can probably be rationalised further.

    Just have a play around.
    • Thread Starter
    Offline

    3
    ReputationRep:
    Thanks got it now

    ( 1 / {sqrt 2 -1} )

    Was failing at the factorise x stage.
    Offline

    16
    ReputationRep:
    Could you not get rid of the " square root of 2" by squaring it (giving you 2) and then squaring the rest of the eqn, before solving it?
    Offline

    4
    ReputationRep:
    (Original post by Thrug)
    Thanks got it now

    ( 1 / {sqrt 2 -1} )

    Was failing at the factorise x stage.
    you can still take this further by rationalising the denominator which you would be expected to do. I think you should get my previous answer....
    Offline

    4
    ReputationRep:
    (Original post by ScottishShortiex)
    Could you not get rid of the " square root of 2" by squaring it (giving you 2) and then squaring the rest of the eqn, before solving it?
    i dont think you could because you would also have to sqaure the 'x' in turn which would not be solving the equation...
    • PS Helper
    Offline

    14
    PS Helper
    (Original post by hdiriaur)
    you can still take this further by rationalising the denominator which you would be expected to do. I think you should get my previous answer....
    That's not what you get when you rationalise the denominator, although I agree that rationalising the denominator would be a good thing to do.
    • Thread Starter
    Offline

    3
    ReputationRep:
    By rationalising the denominator I got  \sqrt 2 - 1
    Offline

    19
    ReputationRep:
    (Original post by Thrug)
    Thanks got it now

    ( 1 / {sqrt 2 -1} )

    Was failing at the factorise x stage.
    It should be 1/(SQRT[2]+1), which simplifies to SQRT[2]-1 (as you've now found).

    Try substituting that into the original equation to test it.
    Offline

    4
    ReputationRep:
    (Original post by nuodai)
    That's not what you get when you rationalise the denominator, although I agree that rationalising the denominator would be a good thing to do.
    oops, thanks for pointing that out! erm in which case would it be, ?
    • PS Helper
    Offline

    14
    PS Helper
    (Original post by hdiriaur)
    oops, thanks for pointing that out! erm in which case would it be, ?
    Yup.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: September 25, 2010

University open days

  • University of Exeter
    Undergraduate Open Days - Exeter Campus Undergraduate
    Wed, 24 Oct '18
  • University of Bradford
    Faculty of Health Studies Postgraduate
    Wed, 24 Oct '18
  • Northumbria University
    All faculties Undergraduate
    Wed, 24 Oct '18
Poll
Do protests make a difference in political decisions?
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

Equations

Best calculators for A level Maths

Tips on which model to get

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.