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

MAT question

    • Thread Starter
    Offline

    1
    ReputationRep:
    Name:  20161006_152124-1.jpg
Views: 38
Size:  127.6 KB

    Could I have some assistance to do this problem ?
    Online

    3
    ReputationRep:
    (Original post by JackSpinner1)
    Name:  20161006_152124-1.jpg
Views: 38
Size:  127.6 KB

    Could I have some assistance to do this problem ?
    Have you made any progress? Post all your working / ideas.

    If you don't know where to start then I would begin by getting rid of the logs to make things easier e.g.

    \log_b a = 2 \Rightarrow a = b^2
    • Thread Starter
    Offline

    1
    ReputationRep:
    I ended up with a=b^2, c-3 = b^3 and c+5 = a^2. from these equations I arrived c-3 = a(a) and so c-3 and c+5 = a^2. Would that show that this is contradictory?
    Online

    3
    ReputationRep:
    (Original post by JackSpinner1)
    I ended up with a=b^2, c-3 = b^3 and c+5 = a^2. from these equations I arrived c-3 = a(a) and so c-3 and c+5 = a^2. Would that show that this is contradictory?
    c-3 = a(a)

    How did you get that?
    • Thread Starter
    Offline

    1
    ReputationRep:
    My bad, I see what i did wrong there
    • Thread Starter
    Offline

    1
    ReputationRep:
    Could i have help of where to go from here, and what does the 'specifies a uniquely' mean as one of the solutions.
    Online

    3
    ReputationRep:
    (Original post by JackSpinner1)
    Could i have help of where to go from here, and what does the 'specifies a uniquely' mean as one of the solutions.
    That means that there is a single value of 'a' that satisfies these equations.

    So you have a=b^2, c-3 = b^3 and c+5 = a^2

    It shouldn't be too hard to eliminate a and c from these equations and leave an equation only in terms of b. Have you tried that? Post all your algebra if you get stuck.
    • Thread Starter
    Offline

    1
    ReputationRep:
    I ended up with c+5 = b^4 by subbing in a=b^2 into the c+5 equation.
    I then subbed in c=b^3+3 into c+5=b^4 to get b^4-b^3=8. Solved for b i got 2 and the other solution has to be negative so i disregarded it, so i got b =2 c= 11 and a = 4.
    And so A is the solution?
 
 
 
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.