Turn on thread page Beta
    • Thread Starter
    Offline

    12
    ReputationRep:
     \frac{6}{x} \times x^2= 6x, apparently.

    Why is this the case? Does  \frac{6}{x} \times x not equal  6x ?

    Edit: This is in the context of an inequality, not an equation. I do not know if this applies to equations, it merely appeared as an example in my textbook and I would like to understand why.
    Offline

    20
    ReputationRep:
    6/x times x just equals 6. The x cancels.
    Offline

    15
    ReputationRep:
    (Original post by Illidan2)
     \frac{6}{x} \times x^2= 6x, apparently.

    Why is this the case? Does  \frac{6}{x} \times x not equal  6x ?
    \frac{6}{x} \times x \equiv \dfrac{6x}{x}

    x is a common factor in both the numerator and denominator, so cancels out (provided that x \neq 0)
    Offline

    10
    ReputationRep:
    Correct me if wrong, but surely 6/x × x= 6? If you had 2/5 × 5 it would be 2, so doesn't it work the same way with variables? So therefore 6/x × x^2 = 6x.
    • Thread Starter
    Offline

    12
    ReputationRep:
    Oh! I see. Now that it has been pointed out, it seems so obvious to me. Thank you, guys!
    Offline

    8
    ReputationRep:
    (Original post by Illidan2)
     \frac{6}{x} \times x^2= 6x, apparently.

    Why is this the case? Does  \frac{6}{x} \times x not equal  6x ?

    Edit: This is in the context of an inequality, not an equation. I do not know if this applies to equations, it merely appeared as an example in my textbook and I would like to understand why.
    Multiplying by just x cancels out the x dividing the 6 and leaves just 6.

    Think of it without at x but just as a number eg 7
    (6/7) x 7 = 6 not 6*7
    Offline

    21
    ReputationRep:
    (Original post by Illidan2)
     \frac{6}{x} \times x^2= 6x, apparently.

    Why is this the case? Does  \frac{6}{x} \times x not equal  6x ?

    Edit: This is in the context of an inequality, not an equation. I do not know if this applies to equations, it merely appeared as an example in my textbook and I would like to understand why.
    it does but in terms of inequalities when multiplying you should always multiply by the square as x can be negative or positive. If x was negative it would flip the sign but we don't know if its negative or positive so we square it. x^2 will always be positive
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: October 22, 2017
The home of Results and Clearing

1,349

people online now

1,567,000

students helped last year

University open days

  1. Bournemouth University
    Clearing Open Day Undergraduate
    Fri, 17 Aug '18
  2. University of Bolton
    Undergraduate Open Day Undergraduate
    Fri, 17 Aug '18
  3. Bishop Grosseteste University
    All Courses Undergraduate
    Fri, 17 Aug '18
Poll
Will you be tempted to trade up and get out of your firm offer on results day?
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.