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Thread: Please help to solve this inequality

  1. #1
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    Please help to solve this inequality

    The post reads: If you replace the equal sign of an equation with the inequality sign, there is never a time when the same value will be a solution to both, namely due to the fact that a solution less than or greater than never be equal to the same solution.

    Solve: 6x + 7 > 15 x = 1 Can this be solved with the factor given for X. I do not think so, How am I suppose to solve this can someone help me to understand the steps that are needed to solve this inequality
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  2. #2
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    Quote Originally Posted by OneidaFL View Post
    The post reads: If you replace the equal sign of an equation with the inequality sign, there is never a time when the same value will be a solution to both, namely due to the fact that a solution less than or greater than never be equal to the same solution.

    Solve: 6x + 7 > 15 x = 1 Can this be solved with the factor given for X. I do not think so, How am I suppose to solve this can someone help me to understand the steps that are needed to solve this inequality
    I'm assuming the "equal sign" is a typo ... do you mean the inequality

    $\displaystyle 6x+7 > 15x+1$ ?

    if so ...

    subtract $\displaystyle 6x$ and $\displaystyle 1$ from both sides ...

    $\displaystyle 6 > 9x$

    divide both sides by $\displaystyle 9$

    $\displaystyle \frac{6}{9} > x$

    reduce and rewrite ...

    $\displaystyle x < \frac{2}{3}$
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  3. #3
    Member rtblue's Avatar
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    Sorry. I didn't not recognize that the = sign would be a +. I agree with skeeter.
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  4. #4
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    unfortunately I think that the student was trying to give the value of x=1 for the following
    problem which read: 6x + 7 > 15 that is why I cannot figure it out. Can you please help?
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  5. #5
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    Smile Correction for inequality question

    This is the actual problem: 6x + 7 > 15

    I need to know how to figure this out. The student had given the value of x to be 1. That just doesn't make sense to me.

    Thank You!
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  6. #6
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    $\displaystyle 6x + 7 > 15$

    $\displaystyle 6x + 7 {\color{red}-7}> 15{\color{red}-7}$

    $\displaystyle 6x > 8$

    $\displaystyle \frac{6x}{{\color{red}6}} > \frac{8}{{\color{red}6}}$

    $\displaystyle x > \frac{8}{6} \approx 1.33$
    Last edited by mr fantastic; May 21st 2010 at 02:48 PM. Reason: Moved from thread created by duplicate post.
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  7. #7
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    Quote Originally Posted by OneidaFL View Post
    unfortunately I think that the student was trying to give the value of x=1 for the following
    problem which read: 6x + 7 > 15 that is why I cannot figure it out. Can you please help?
    The solution is the same as you would do for equation. If you had $\displaystyle 6x +7 = 15$ how would you solve?

    I guess you would do this.

    $\displaystyle 6x+7 = 15$
    $\displaystyle
    6x = 15-7$

    $\displaystyle x = 8/6 = 4/3$

    Now it is the same for inequality.

    $\displaystyle 6x+7 > 15$ meanining $\displaystyle 6x > 15-7$, meaning $\displaystyle 6x > 8 $, meaning $\displaystyle x > 4/3$
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  8. #8
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    most probably, the longest thread I've seen over a linear inequality.
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  9. #9
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    Quote Originally Posted by skeeter View Post
    most probably, the longest thread I've seen over a linear inequality.
    And it ain't gettin' any longer.

    Thread closed.
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