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Homework Help: Have I rearraged this formula correctly?

  1. Jan 28, 2010 #1
    I have to make m the subject:

    3(2m - t) = 2t + 7

    This is my attempt:

    m = (0.5t + 3.5 / 1.5) + 0.5t
     
  2. jcsd
  3. Jan 28, 2010 #2

    berkeman

    User Avatar

    Staff: Mentor

    Could you please show each step?
     
  4. Jan 28, 2010 #3
    sure
    3(2m - t) = 2t + 7
    move the 3 to the left side

    2m - t = 2t + 7 / 3

    move the -t to the left side
    2m = (2t + 7 /3) +t

    divide both sides by 2
    m = (t + 3.5 / 1.5) +0.5t

    and I realise this is slightly different to the 1st solution that I put up. 2t / 2 is of course t, not 0.5t.

    Anyway, is it right?
     
  5. Jan 28, 2010 #4

    Mark44

    Staff: Mentor

    No, it's not right. When you divide 7/3 by 2 you should get 7/6, not 3.5/1.5, which is equal to 7/3.

    BTW, You really ought to learn which is left and which is right...

    Also, in your second equation, the right side should have parentheses:
    2m - t = (2t + 7)/3

    In the following line you added parenthese, but they are not where you need them. This equation should be written like so:
    2m = (2t + 7)/3 +t

    Finally, the expression you have for m, besides being incorrect, should be written more simply, with the t terms combined.
     
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