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Math Help - Rearrange formula

  1. #1
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    Rearrange formula

    i need to make c the subject in this formula? any help would be nice please.

    s=c+mt
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  2. #2
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    Quote Originally Posted by nexer View Post
    i need to make c the subject in this formula? any help would be nice please.

    s=c+mt
    c = s - mt
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  3. #3
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    Quote Originally Posted by nexer View Post
    i need to make c the subject in this formula? any help would be nice please.
    s=c+mt
    Nexer, any reason why you couldn't solve that?
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  4. #4
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    Quote Originally Posted by Wilmer View Post
    Nexer, any reason why you couldn't solve that?
    because he has just started learning algebra
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  5. #5
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    feel like i really suck at algebra, like i also need to know to rearrange the formula so i can make t the subject

    S=c+mt

    i got s-c/m=t

    ? Guessing wrong?
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  6. #6
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    Quote Originally Posted by nexer View Post
    feel like i really suck at algebra, like i also need to know to rearrange the formula so i can make t the subject

    S=c+mt

    i got s-c/m=t

    ? Guessing wrong?
    The problem is "guessing" at all! The only reason c, in s= c+ mt is not "by itself" already is that mt is added to it. To "undo" that, do the opposite: the opposite of "add mt" is "subtract mt". Subtract mt from both sides to get s-mt= c which is the same as c= s- mt.

    Now, t, in s= c+ mt is not "by itself" is that two things have been done to it: to get to "c+ mt" from t, you would "multiply by m" and "add c" in that order. To "undo" it, do the opposite things in the opposite order: first "subtract c" then "divide by t".

    From s= c+ mt, subtracting c from both sides gives s- c= mt. Now divide both sides by m- but be sure to show that the entire right side, s- c, is divided by m, not just "c": use parentheses (s-c)/m= t, not "s- c/m" which means s- (c/m)!
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  7. #7
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    Sorry, it wasn't actually a "guess" i tried to work it out, that final answer is what i had on paper!
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  8. #8
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    Geezzzz...can your teacher not help you?
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