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j2lie

  • one year ago

If the slope of the line that passes through the points (a,0) and (1,-2) is 1/2, what is the value of a? @jim_thompson5910

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  1. freckles
    • one year ago
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    have you applied the slope formula?

  2. freckles
    • one year ago
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    \[m=\frac{y_2-y_1}{x_2-x_1} \]

  3. j2lie
    • one year ago
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    No. I do not know that to do that with this problem.

  4. freckles
    • one year ago
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    well you are given two points on a line and the slope ... which makes me think slope formula since only one of the values is unknown in the pairs given you are given m is 1/2 (x1,y1)=(1,-2) and (x2,y2)=(a,0)

  5. freckles
    • one year ago
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    \[\frac{1}{2}=\frac{0-(-2)}{a-1}\] solve for a

  6. j2lie
    • one year ago
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    a = -2

  7. freckles
    • one year ago
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    how did you get that?

  8. j2lie
    • one year ago
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    0 + 2 is 2 and a - 1 is -1

  9. freckles
    • one year ago
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    it might make it easier on you if you flip both sides \[\frac{2}{1}=\frac{a-1}{0-(-2)}\] see if you can solve now

  10. freckles
    • one year ago
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    by the way 2/1 is just 2

  11. jdoe0001
    • one year ago
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    \(\bf \begin{array}{lllll} &x_1&y_1&x_2&y_2\\ % (a,b) &({\color{red}{ a}}\quad ,&{\color{blue}{ 0}})\quad % (c,d) &({\color{red}{ 1}}\quad ,&{\color{blue}{ -2}}) \end{array} \\\quad \\ % slope = m slope = {\color{green}{ m}}= \cfrac{rise}{run} \implies \cfrac{{\color{blue}{ y_2}}-{\color{blue}{ y_1}}}{{\color{red}{ x_2}}-{\color{red}{ x_1}}}\implies \cfrac{{\color{blue}{ -2}}-{\color{blue}{ 0}}}{{\color{red}{ 1}}-{\color{red}{ a}}}=\cfrac{1}{2}\)

  12. j2lie
    • one year ago
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    I am confused now.

  13. freckles
    • one year ago
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    confused on how to solve 2=(a-1)/2 for a?

  14. j2lie
    • one year ago
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    Yes.

  15. freckles
    • one year ago
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    are confused on the flipping part? confused on the equation we got?

  16. j2lie
    • one year ago
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    I am confused on solving with A.

  17. freckles
    • one year ago
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    solving with A?

  18. freckles
    • one year ago
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    what does that mean

  19. freckles
    • one year ago
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    you mean solve for a?

  20. j2lie
    • one year ago
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    The variable is A in the equation

  21. freckles
    • one year ago
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    don't we have a not A? \[\frac{1}{2}=\frac{0-(-2)}{a-1} \\ \\ 0-(-2) \text{ is the same as } 2 \\ \text{ you have } \\ \frac{1}{2}=\frac{2}{a-1}\]

  22. freckles
    • one year ago
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    you can flip both sides like I did earlier \[\frac{2}{1}=\frac{a-1}{2} \\ \text{ now } \frac{2}{1}=2 \\ 2=\frac{a-1}{2}\]

  23. freckles
    • one year ago
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    try to undo that division by 2 ...multiply 2 on both sides

  24. j2lie
    • one year ago
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    1=4/a-1?

  25. freckles
    • one year ago
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    well 2 times 2 is 4 not 1 and how did you put a-1 back in the denominator? also 2/2=1 not 4...

  26. freckles
    • one year ago
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    oh you went backwards

  27. j2lie
    • one year ago
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    it is 1/2 times 2

  28. freckles
    • one year ago
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    do you see this equation 2=(a-1)/2 I was asking you multiply this equation by 2 on both sides

  29. freckles
    • one year ago
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    this gives you 4=a-1

  30. j2lie
    • one year ago
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    how did you get 2?

  31. freckles
    • one year ago
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    @Jhannybean you can finish i have to leave I'm sorry

  32. j2lie
    • one year ago
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    I get it now.

  33. Jhannybean
    • one year ago
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    \[2=\frac{a-1}{2} \implies 4 = a-1 \implies a= 4+1\]

  34. j2lie
    • one year ago
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    That is what I got.

  35. j2lie
    • one year ago
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    Thank you.

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