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Can someone explain this to me please.

  • 31-07-2023 03:59AM
    #1
    mondeoman72
    Registered Users, Registered Users 2 Posts: 1,069 ✭✭✭


    image.png

    I am brushing up on my maths and bashing Khan academy. Dont ask! Im unsure about something. In step 4/5 above a(3a+3)/3a = 3a(a+1)/3a Should it not be 3a^2+3a/3a


    Thanks folks



Comments

  • #2
    Mellor
    Registered Users, Registered Users 2 Posts: 40,589 ✭✭✭✭Mellor


     In step 4/5 above a(3a+3)/3a = 3a(a+1)/3a Should it not be 3a^2+3a/3a

    No. They are not trying to carrying out all the operations in the top line (the above would be correct). They are trying to represent the top line in terms of 3a in order to cancel out the denominator. The easiest way to do that is take 3 outside the bracket.

    a(3a+3)
3a(a+1)

    You could multiple it out to 3a^2+3a. And then take 3a outside the bracket to arrive at the same result, but its extra steps, why bother.

     a(3a+3)
3a^2+3a
3a(a+1)




  • #3
    TheBody
    Registered Users, Registered Users 2 Posts: 5,657 ✭✭✭TheBody


    Your answer is fine too but it's not in it's simplest form. It's like saying the answer to some problem is 2/4 instead of 1/2. Both are the same but it's good practice to reduce where possible. So, by factoring out the 3a from the top and bottom, and cancelling, they are leaving the fraction in its simpliest form.



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