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anonymous

  • one year ago

Identify the axis of symmetry and vertex of f(x) = –2x^2 –2x–1. Axis of symmetry: x = 0.5; Vertex: (0.5, – 0.50) Axis of symmetry: x = – 0.5; Vertex: (– 0.5, 0.50) Axis of symmetry: x = – 0.5; Vertex: (– 0.5, – 0.50) Axis of symmetry: x = 0.5; Vertex: (– 0.5, – 0.50)

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  1. anonymous
    • one year ago
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    @fashionismybesty

  2. anonymous
    • one year ago
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    http://www.mathway.com/graph/NTUxODk this is an amazing site for graphing

  3. freckles
    • one year ago
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    Do you know how to write in vertex form? If involves completing the square? \[f(x)=-2x^2-2x-1 \\ f(x)=-2(x^2+x)-1 \\ f(x)=-2(x^2+x+L)-1+2L \\ \text{ notice } -2L+2L=0 \\ \text{ we need to figure out what } L \text{ needs to be to } \\ \text{ complete the square inside that one ( )}\]

  4. Nnesha
    • one year ago
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    or http://openstudy.com/study#/updates/55de281ae4b0f9297e9bc5e7 :=)

  5. triciaal
    • one year ago
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    |dw:1440639916432:dw|

  6. triciaal
    • one year ago
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    vertex form a(x-h)^2 + k = 0 vertex (h, k) axis of symmetry x = h

  7. anonymous
    • one year ago
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    It's really confusing.

  8. Nnesha
    • one year ago
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    do you know what 's a b and c in the equation ?

  9. anonymous
    • one year ago
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    No.. I'm really confused with math, I sometimes know things but like need to refresh my mind.. I know some rules in Arabic and some in English.. Because I took math in both languages and now im really really confused

  10. Nnesha
    • one year ago
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    \(\color{blue}{\text{Originally Posted by}}\) @Nnesha or http://openstudy.com/study#/updates/55de281ae4b0f9297e9bc5e7 :=) \(\color{blue}{\text{End of Quote}}\) didn't notice that link doesn't work http://openstudy.com/study#/updates/55daa403e4b0a0d51271c948

  11. Nnesha
    • one year ago
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    ahh i see okay

  12. Nnesha
    • one year ago
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    quadratic equation is \[\huge\rm Ax^2+Bx+C=0\] where a=leading coefficient b=middle term c= constant term

  13. Nnesha
    • one year ago
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    quadratic equation is \[\huge\rm\color{red}{ A}x^2+\color{blue}{B}x+\color{pink}{C} \] where a=leading coefficient b=middle term c= constant term \[\huge\rm \color{Red}{–2}x^2 \color{blue}{–2}x\color{pink}{–1}\] so what is a and b equal to in that equation ?

  14. Nnesha
    • one year ago
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    let me if u didn't understand :=)

  15. anonymous
    • one year ago
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    2? @Nnesha

  16. Nnesha
    • one year ago
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    not just negative 2 a=-2 b=-2 now use the formula to find x-coordinate of vertex \[\huge\rm \frac{ -b }{ 2a }\] replace b and a with -2

  17. anonymous
    • one year ago
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    so it would be -2/2^-2?

  18. Nnesha
    • one year ago
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    no \[\frac{ -(-2) }{ 2(-2)}\] don't forget to put the parentheses there is negative sign in the formula and b is also negative and at the denominator it's 2 times -2 not 2 to the -2 power

  19. Nnesha
    • one year ago
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    2(-2) is n't same as 2^(-2)

  20. anonymous
    • one year ago
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    Ohh okay

  21. Nnesha
    • one year ago
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    now simplify that

  22. anonymous
    • one year ago
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    it would equal -2?

  23. Nnesha
    • one year ago
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    no

  24. Nnesha
    • one year ago
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    \[\huge\rm \frac{ -(-2) }{ 2(-2)}\] what did you get at the numerator ?

  25. anonymous
    • one year ago
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    aren't we supposed to divide the numerator and denominator by -2

  26. Nnesha
    • one year ago
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    yes right \[\huge\rm \frac{ -\cancel{(-2)} }{ 2\cancel{(-2)}}\] what would you get at the top ?

  27. anonymous
    • one year ago
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    the negative sign

  28. anonymous
    • one year ago
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    0?

  29. Nnesha
    • one year ago
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    no there is one

  30. Nnesha
    • one year ago
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    invisible one :=)

  31. Nnesha
    • one year ago
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    so it should be -1/2

  32. Nnesha
    • one year ago
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    just like 2/2 =1

  33. anonymous
    • one year ago
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    Oh okay

  34. Nnesha
    • one year ago
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    yes so that's the x-coordinate of the vertex which is also the axis of symmetry

  35. Nnesha
    • one year ago
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    now replace all x for -1/2 into the f(x) function

  36. Nnesha
    • one year ago
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    \[\huge\rm f(-0.5) = –2x^2 –2x–1.\] -1/2 = -0.5 so now replace all x's for -0.5 then solve

  37. anonymous
    • one year ago
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    f(-0.5) = -2(-0.5)^2-2(0.5)-1

  38. Nnesha
    • one year ago
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    yes right now solve right side :=) to find y-coordinate of the vertex

  39. anonymous
    • one year ago
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    equals -0.5?

  40. Nnesha
    • one year ago
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    yes right that's y-coordinate of vertex

  41. Nnesha
    • one year ago
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    done!

  42. anonymous
    • one year ago
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    but the choices have 0.50.. from where did that come from @Nnesha

  43. Nnesha
    • one year ago
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    ohh that's the same .50 or .5

  44. anonymous
    • one year ago
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    so the answer is C) Axis of symmetry: x = – 0.5; Vertex: (– 0.5, – 0.50)

  45. Nnesha
    • one year ago
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    yep

  46. Nnesha
    • one year ago
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    subtract .50-.5 you will get 0 thats mean both are the same

  47. anonymous
    • one year ago
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    Oh thank you very much!

  48. Nnesha
    • one year ago
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    my pleasure!

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