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Homework Help: Equations -check pls!

  1. Oct 18, 2005 #1
    Solve the equations:
    a) 253x = 1/52-x
    This is what i've done but i don't know if it's right so i need someone to check it for me please.
    (52)3x = (5-1)2-x
    6x = -2+x (x powers)
    5x=-2
    x= -2/5
    b)3x-1/2 - 4 = 0
    errm....i'm kinda stuck on this one, could someone start me off please?
    3x-1/2 = 4
    c) find the value of y
    4y+1=82y-1
    here's what i did:
    (22)y+1 = (23)2y-1
    2y+2=6y-3 (powers)
    4y-5=0
    y=5/4
    Is that right?
    Thanks in advance!
     
  2. jcsd
  3. Oct 18, 2005 #2
    (a) and (c) appear to be correct, as for (b)

    Try and get x on it's own, i would continue by:

    3x^-1/2 = 4
    1/3x^1/2 = 4
    12x^1/2 = 1
     
  4. Oct 19, 2005 #3

    Ouabache

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    you have the right concept however, something seems fishy :uhh:
    why did you invert 3x^-1/2? to become 1/3x^1/2?
    It didn't say (3x)^-1/2 ..
    I would say 3x^-1/2 = 3/(x^1/2).
    Then 3/(x^(1/2)) = 4
    4x^(1/2) = 3
    x^(1/2) = 3/4 etc...
     
  5. Oct 19, 2005 #4
    Whoops you're right Ouabache sorry about that discombobulated, my escuse is it was late when i did that reply :blushing:, anyway mistake understood, i did think 1/144 was a bit of an odd answer...
     
  6. Oct 19, 2005 #5
    Thanks alot guys, i worked it out and I got the answer x= 9/16
     
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