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Math Help - Solving Algebraically.

  1. #1
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    Solving Algebraically.

    Solving Algebraically.
    1/x+1/3x=x/12
    I got to 36x+12x=3x^3, tell me if I am wrong! Many thanks!
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  2. #2
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    Quote Originally Posted by BabyMilo View Post
    Solving Algebraically. I got to 36x+12x=3x^3, tell me if I am wrong! Many thanks!
    Yes, you are wrong.

    You have \frac{1}{x}+ \frac{3}{x}= \frac{1}{12}
    The "common denominator" is 12x so you can get rid of the fractions by multiplying the entire equation by 12x. Simplify the fractions in \frac{12x}{x}+ \frac{3(12x)}{x}= \frac{12x}{12}
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  3. #3
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    Quote Originally Posted by HallsofIvy View Post
    Yes, you are wrong.

    You have \frac{1}{x}+ \frac{3}{x}= \frac{1}{12}
    The "common denominator" is 12x so you can get rid of the fractions by multiplying the entire equation by 12x. Simplify the fractions in \frac{12x}{x}+ \frac{3(12x)}{x}= \frac{12x}{12}
    Is that the answer?
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  4. #4
    Member SENTINEL4's Avatar
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    \frac{1}{x}+\frac{1}{3x}=\frac{x}{12} \Rightarrow
    3(\frac{1}{x})+\frac{1}{3x}=\frac{x}{12} \Rightarrow
    \frac{3}{3x}+\frac{1}{3x}=\frac{x}{12} \Rightarrow
    \frac{3+1}{3x}=\frac{x}{12} \Rightarrow
    \frac{4}{3x}=\frac{x}{12} \Rightarrow

    4(12)=x(3x) \Rightarrow 48=3 x^2 \Rightarrow 3 x^2-48=0 \Rightarrow

    3( x^2-16)=0 \Rightarrow ( x^2-16)=0 \Rightarrow x^2=16 \Rightarrow

    x=4 or x=-4
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  5. #5
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    Quote Originally Posted by SENTINEL4 View Post
    \frac{1}{x}+\frac{1}{3x}=\frac{x}{12} \Rightarrow
    3(\frac{1}{x})+\frac{1}{3x}=\frac{x}{12} \Rightarrow
    \frac{3}{3x}+\frac{1}{3x}=\frac{x}{12} \Rightarrow
    \frac{3+1}{3x}=\frac{x}{12} \Rightarrow
    \frac{4}{3x}=\frac{x}{12} \Rightarrow

    4(12)=x(3x) \Rightarrow 48=3 x^2 \Rightarrow 3 x^2-48=0 \Rightarrow

    3( x^2-16)=0 \Rightarrow ( x^2-16)=0 \Rightarrow x^2=16 \Rightarrow

    x=4 or x=-4
    Many Thanks! I know it's right as I have checked but where did you get the 3 from on the second line?
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  6. #6
    Member SENTINEL4's Avatar
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    \frac{1}{x}+\frac{1}{3x} we have these two fractions which are disimilar. We want similar fractions to add them. Similar fractions are those which have same denominators (bottom number).
    Here the two denominators are x and 3x, so we multiply the first fraction with 3 (both numerator and denominator) and we have \frac{3}{3x}.
    Now that are similar we add their numerators.

    I hope i make you understand, english isn't my mother language
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