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Math Help - Solving linear equations.

  1. #1
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    Solving linear equations.

    How can I solve this?

    ((5p-4)/6) - ((2p+3)/2) = 7

    In my text book it says the answer is p = -55 but I've tried and can't get this.

    Thanks.
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  2. #2
    Moo
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    Hello,

    Put the fractions in the left hand side of the equality on the same denominator (6).

    Then, do the same for 7. 7=42/6 and multiply both sides by 6.

    After that, you may solve it like a normal equation... Can you show a bit of your work ? To see if you're going the right way
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  3. #3
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    Quote Originally Posted by Moo View Post
    Hello,

    Put the fractions in the left hand side of the equality on the same denominator (6).

    Then, do the same for 7. 7=42/6 and multiply both sides by 6.

    After that, you may solve it like a normal equation... Can you show a bit of your work ? To see if you're going the right way
    I keep ending up with p = -37

    I did...

    ((5p-4)/6) - ((6p+9)/6) = 42/6

    5p-4-6p+9=42 (multiplied by 6)

    -p+5=42

    -p=37

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  4. #4
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    Quote Originally Posted by Mymble View Post
    I keep ending up with p = -37

    I did...

    ((5p-4)/6) - ((6p+9)/6) = 42/6

    5p-4- (6p+9) =42 (multiplied by 6) Mr F says: USE BRACKETS!

    5p - 4 - 6p - 9 = 42 etc.

    -p+5=42

    -p=37

    Ahhhhh the benefits of showing working. What you should have done is in red. The really important thing is in blue!
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  5. #5
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    Quote Originally Posted by Mymble View Post
    I keep ending up with p = -37

    I did...

    ((5p-4)/6) - ((6p+9)/6) = 42/6

    5p-4-6p+9=42 (multiplied by 6)

    -p+5=42

    -p=37

    Quote Originally Posted by mr fantastic View Post
    Ahhhhh the benefits of showing working. What you should have done is in red. The really important thing is in blue!
    Oh!
    I think I understand that...
    Because it's minus (6p+9) the +9 becomes -9?

    So...
    ((5p-4)/6) - ((6p+9)/6) = 42/6

    5p-4-6p-9=42

    -p+=55

    -p=55

    p=-55

    Thanks so much!
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  6. #6
    Moo
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    That's it ^^

    The - sign is distributed into the parenthesis

    When you substract : -(a+b) this means you substract a AND b, so it's like -a-b
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  7. #7
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    Quote Originally Posted by Mymble View Post
    Oh!
    I think I understand that...
    Because it's minus (6p+9) the +9 becomes -9?

    So...
    ((5p-4)/6) - ((6p+9)/6) = 42/6

    5p-4-6p-9=42

    -p+=55

    -p=55

    p=-55

    Thanks so much!


    ps: And thankyou for your lovely manners!
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  8. #8
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    Thankyou very much for your help both of you.

    Sorry if it seemed a silly mistake.
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  9. #9
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    Quote Originally Posted by Mymble View Post
    Thankyou very much for your help both of you.

    Sorry if it seemed a silly mistake.
    As long as you learn from it, it's certainly not silly.
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